Over 3% of asthmatic patients are affected by a particularly severe form of the disease (“severe asthma”, SA) which is often refractory to standard treatment. Airway remodeling (AR), which can be considered a critical characteristic of approximately half of all patients with SA and currently thought to be the main mechanism triggering fixed airway obstruction (FAO), seems to be a key factor affecting a patient’s outcome. Despite the collective efforts of internationally renowned experts, to date only a few biomarkers indicative of AR and no recognizable biomarkers of lung parenchymal remodeling have been identified. This work examines the pathogenesis of airway and lung parenchymal remodeling and the serum biomarkers that may be able to identify the severe asthmatic patients who may develop FAO. The study also aims to examine if Krebs von den Lungen-6 (KL-6) could be considered a diagnostic biomarker of lung structural damage in SA.

Publicly Available May 16, 2023

Safety monitoring of drug-induced muscle injury and rhabdomyolysis: a biomarker-guided approach for clinical practice and drug trials

Patryk Ostrowski, Michał Bonczar, Aida-Elena Avram, Giuseppe Lippi, Brandon M. Henry

Page range: 1688-1699

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Abstract

Skeletal muscle tissue (SKM) may be damaged due to mechanical, metabolic, and exertional causes. However, drug-induced myopathy is among the most frequent causes of muscle disease. The clinical picture of drug-induced myopathies may be highly variable. It may present as asymptomatic or mild myalgias, with or without muscle weakness, which are likely underreported. However, it may also appear as chronic myopathy with severe weakness and, rarely, even as massive rhabdomyolysis with acute kidney injury (AKI). Unfortunately, the available biomarkers for SKM injury do not fully meet the needs for satisfactory detection of drug-induced damage, both in clinical and research settings, mainly due to their low sensitivity and specificity. Therefore, the present study proposes a strategy for drug safety monitoring using the available biomarkers of SKM injury. Moreover, we will discuss mechanisms of drug-induced SKM injury, traditional laboratory testing for SKM injury, and novel skeletal myocyte biomarkers under investigation. This can be incredibly useful in both clinical practice and for de-challenge/re-challenge investigational trials where the risk of drug-induced SKM injury is present.

Mini Review

May 3, 2023

Concise review on the combined use of immunocapture, mass spectrometry and liquid chromatography for clinical applications

Philippe Massonnet, Elodie Grifnée, Jordi Farré-Segura, Justine Demeuse, Loreen Huyghebaert, Thomas Dubrowski, Patrice Dufour, Matthieu Schoumacher, Stéphanie Peeters, Caroline Le Goff, Etienne Cavalier

Page range: 1700-1707

Abstract

Immunocapture is now a well-established method for sample preparation prior to quantitation of peptides and proteins in complex matrices. This short review will give an overview of some clinical applications of immunocapture methods, as well as protocols with and without enzymatic digestion in a clinical context. The advantages and limitations of both approaches are discussed in detail. Challenges related to the choice of mass spectrometer are also discussed. Top-down, middle-down, and bottom-up approaches are discussed. Even though immunocapture has its limitations, its main advantage is that it provides an additional dimension of separation and/or isolation when working with peptides and proteins. Overall, this short review demonstrates the potential of such techniques in the field of proteomics-based clinical medicine and paves the way for better personalized medicine.

Opinion Paper

Publicly Available April 6, 2023

Recommendation for the design of stability studies on clinical specimens

Rubén Gomez-Rioja, Alexander Von Meyer, Michael Cornes, Sean Costelloe, Pieter Vermeersch, Ana-Maria Simundic, Mads Nybo, Geoffrey Stuart Baird, Gunn B.B. Kristensen, Janne Cadamuro, on behalf of the European Federation of Clinical Chemistry, Laboratory Medicine (EFLM) Working Group Preanalytical Phase (WG-PRE)

Page range: 1708-1718

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Abstract

Objectives Knowledge of the stability of analytes in clinical specimens is a prerequisite for proper transport and preservation of samples to avoid laboratory errors. The new version of ISO 15189:2022 and the European directive 2017/746 increase the requirements on this topic for manufacturers and laboratories. Within the project to generate a stability database of European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group Preanalytical Phase (WG-PRE), the need to standardise and improve the quality of published stability studies has been detected, being a manifest deficit the absence of international guidelines for the performance of stability studies on clinical specimens. Methods These recommendations have been developed and summarised by consensus of the WG-PRE and are intended primarily to improve the quality of sample stability claims included in information for users provided by assay supplier companies, according to the requirements of the new European regulations and standards for accreditation. Results This document provides general recommendations for the performance of stability studies, oriented to the estimation of instability equations in the usual working conditions, allowing flexible adaptation of the maximum permissible error specifications to obtain stability limits adapted to the intended use. Conclusions We present this recommendation based on the opinions of the EFLM WG-PRE group for the standardisation and improvement of stability studies, with the intention to improve the quality of the studies and the transferability of their results to laboratories.

General Clinical Chemistry and Laboratory Medicine

Open Access April 18, 2023

Assessment of WHO 07/202 reference material and human serum pools for commutability and for the potential to reduce variability among soluble transferrin receptor assays

Alicia N. Lyle, Jeffrey R. Budd, Victoria M. Kennerley, Bianca N. Smith, Uliana Danilenko, Christine M. Pfeiffer, Hubert W. Vesper

Page range: 1719-1729

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Abstract

Objectives The clinical use of soluble transferrin receptor (sTfR) as an iron status indicator is hindered by a lack of assay standardization and common reference ranges and decision thresholds. In 2009, the WHO and National Institute for Biological Standards and Controls (NIBSC) released a sTfR reference material (RM), 07/202, for assay standardization; however, a comprehensive, formal commutability study was not conducted. Methods This study evaluated the commutability of WHO 07/202 sTfR RM and human serum pools and the impacts of their use as common calibrators. Commutability was assessed for six different measurement procedures (MPs). Serum pools were prepared according to updated CLSI C37-A procedures (C37) or non-C37 procedures. The study design and analyses were based on Parts 2 and 3 of the 2018 IFCC Commutability in Metrological Traceability Working Group’s Recommendations for Commutability Assessment. WHO 07/202 and serum pools were used for instrument/assay and mathematical recalibration, respectively, to determine if their use decreases inter-assay measurement variability for clinical samples. Results The WHO 07/202 RM dilutions were commutable for all 6 MPs assessed and, when used for instrument calibration, decreased inter-assay variability from 208 to 55.7 %. Non-C37 and C37 serum pools were commutable for all 6 MPs assessed and decreased inter-assay variability from 208 to 13.8 % and 4.6 %, respectively, when used for mathematical recalibration. Conclusions All materials evaluated, when used as common calibrators, substantially decreased inter-assay sTfR measurement variability. MP calibration to non-C37 and C37 serum pools may reduce the sTfR IMPBR to a greater extent than WHO 07/202 RM.

Open Access April 13, 2023

veRification: an R Shiny application for laboratory method verification and validation

Edmund H. Wilkes

Page range: 1730-1739

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Abstract

Objectives According to international standards, clinical laboratories are required to verify the performance of assays prior to their implementation in routine practice. This typically involves the assessment of the assay’s imprecision and trueness vs. appropriate targets. The analysis of these data is typically performed using frequentist statistical methods and often requires the use of closed source, proprietary software. The motivation for this paper was therefore to develop an open-source, freely available software capable of performing Bayesian analysis of verification data. Methods The veRification application presented here was developed with the freely available R statistical computing environment, using the Shiny application framework. The codebase is fully open-source and is available as an R package on GitHub. Results The developed application allows the user to analyze imprecision, trueness against external quality assurance, trueness against reference material, method comparison, and diagnostic performance data within a fully Bayesian framework (with frequentist methods also being available for some analyses). Conclusions Bayesian methods can have a steep learning curve and thus the work presented here aims to make Bayesian analyses of clinical laboratory data more accessible. Moreover, the development of the application and seeks to encourage the dissemination of open-source software within the community and provides a framework through which Shiny applications can be developed, shared, and iterated upon.

April 21, 2023

Impact of storage temperature and time before analysis on electrolytes (Na⁺, K⁺, Ca²⁺), lactate, glucose, blood gases (pH, pO₂, pCO₂), tHb, O₂Hb, COHb and MetHb results

Antoine Puravet, Benjamin Rieu, Camille Phere, Samy Kahouadji, Bruno Pereira, Matthieu Jabaudon, Benjamin Andanson, Marina Brailova, Vincent Sapin, Damien Bouvier

Page range: 1740-1749

Abstract

Objectives The objective of our study is to evaluate the effect of storage temperature and time to analysis on arterial blood gas parameters in order to extend the CLSI recommendations. Methods Stability of 12 parameters (pH, pCO₂, pO₂, Na + , K + , Ca 2+ , glucose, lactate, hemoglobin, oxyhemoglobin, carboxyhemoglobin, methemoglobin) measured by GEM PREMIER™ 5000 blood gas analyzer was studied at room temperature and at +4 °C (52 patients). The storage times were 30, 45, 60, 90 and 120 min. Stability was evaluated on the difference from baseline, the difference from the analyte-specific measurement uncertainty applied to the baseline value, and the impact of the variation on the clinical interpretation. Results At room temperature, all parameters except the lactate remained stable for at least 60 min. A statistically significant difference was observed for pH at T45 and T60 and for pCO 2 at T60 without modification of clinical interpretation. For lactate, clinical interpretation was modified from T45 and values were outside the range of acceptability defined by the measurement uncertainty. All parameters except pO 2 remained stable for at least 120 min at +4 °C. Conclusions A one-hour transport at room temperature is compatible with the performance of all the analyses studied except lactate. If the delay exceeds 30 min, the sample should be placed at +4 °C for lactate measurement. If the samples are stored in ice, it is important to note that the pO 2 cannot be interpreted.

Open Access April 6, 2023

The stability of blood gases and CO-oximetry under slushed ice and room temperature conditions

Gerald S. Zavorsky, Xander M.R. van Wijk

Page range: 1750-1759

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Abstract

Objectives Human blood gas stability data is limited to small sample sizes and questionable statistical techniques. We sought to determine the stability of blood gases under room temperature and slushed iced conditions in patients using survival analyses. Methods Whole blood samples from ∼200 patients were stored in plastic syringes and kept at room temperature (22–24 °C) or in slushed ice (0.1–0.2 °C) before analysis. Arterial and venous p O 2 (15–150 mmHg), p CO 2 (16–72 mmHg), pH (6.73–7.52), and the CO-oximetry panel [total hemoglobin (5.4–19.3 g/dL), percentages of oxyhemoglobin (O 2 Hb%, 20–99%), carboxyhemoglobin (COHb, 0.1–5.4%) and methemoglobin (MetHb, 0.2–4.6%)], were measured over 5-time points. The Royal College of Pathologists of Australasia’s (RCPA’s) criteria determined analyte instability. Survival analyses identified storage times at which 5% of the samples for various analytes became unstable. Results COHb and MetHb were stable up to 3 h in slushed ice and at room temperature; p CO 2 , pH was stable at room temperature for about 60 min and 3 h in slushed ice. Slushed ice shortened the storage time before p O 2 became unstable (from 40 to 20 min), and the instability increased when baseline p O 2 was ≥60 mmHg. The storage time for p O 2 , p CO 2 , pH, and CO-oximetry, when measured together, were limited by the p O 2 . Conclusions When assessing p O 2 in plastic syringes, samples kept in slushed ice harm their stability. For simplicity’s sake, the data support storage times for blood gas and CO-oximetry panels of up to 40 min at room temperature if following RCPA guidelines.

April 6, 2023

Elevated levels of renal function tests conferred increased risks of developing various pregnancy complications and adverse perinatal outcomes: insights from a population-based cohort study

Zhengwen Xu, He S. Yang, Lin Liu, Lanlan Meng, Yifan Lu, Lican Han, Guodong Tang, Jing Wang, Lu Chen, Yue Zhang, Yanhong Zhai, Shaofei Su, Zheng Cao

Page range: 1760-1769

Abstract

Objectives Physiological changes during pregnancy can affect the results of renal function tests (RFTs). In this population-based cohort study, we aimed to establish trimester-specific reference intervals (RIs) of RFTs in singleton and twin pregnancies and systematically investigate the relationship between RFTs and adverse pregnancy outcomes. Methods The laboratory results of the first- and third-trimester RFTs, including blood urea nitrogen (BUN), serum uric acid (UA), creatinine (Crea) and cystatin C (Cys C), and the relevant medical records, were retrieved from 29,328 singleton and 840 twin pregnant women who underwent antenatal examinations from November 20, 2017 to January 31, 2021. The trimester-specific RIs of RFTs were estimated with both of the direct observational and the indirect Hoffmann methods. The associations between RTFs and pregnancy complications as well as perinatal outcomes were assessed by logistic regression analysis. Results Maternal RFTs showed no significant difference between the direct RIs established with healthy pregnant women and the calculated RIs derived from the Hoffmann method. In addition, elevated levels of RFTs were associated with increased risks of developing various pregnancy complications and adverse perinatal outcomes. Notably, elevated third-trimester RFTs posed strong risks of preterm birth (PTB) and fetal growth restriction (FGR). Conclusions We established the trimester-specific RIs of RFTs in both singleton and twin pregnancies. Our risk analysis findings underscored the importance of RFTs in identifying women at high risks of developing adverse complications or outcomes during pregnancy.

April 14, 2023

Poor comparability of plasma renin activity measurement in determining patient samples: the status quo and recommendations for harmonization

Zhenni Liu, Lizi Jin, Jie Zeng, Tianjiao Zhang, Jiangtao Zhang, Weiyan Zhou, Chuanbao Zhang

Page range: 1770-1779

Abstract

Objectives This study aims to investigate and update the consistency and comparability of plasma renin activity (PRA) assays in measuring clinical samples. The contributions of recalibration, blank subtraction, and incubation strategies to interchangeability were also explored. Methods Five different laboratories were evaluated using forty-six individual plasma samples, including four liquid chromatography-tandem mass spectrometry (LC‒MS/MS) assays and one chemiluminescence immunoassay (CLIA). Spearman correlation coefficient (R), Passing–Bablok regression, and Bland‒Altman plot analyses were used to evaluate the consistency among assays. Consistency before and after recalibration, blank subtraction, and incubation strategy unification was compared. Results A good correlation was observed among all assays (R>0.93). None of the samples measured by all assays showed coefficient variation (CV) <10 %, and 37 % of samples showed overall CVs >20 %. The 95 % confidence intervals (CIs) for slopes did not contain 1 for most assay pairs. Large relative biases (−85.1–104.2 %) were found, and 76 % (52–93 %) of samples had unacceptable biases. Recalibration reduced the calibration bias. Ignoring blank subtraction improved the comparability across all assays while unifying incubation did not. Conclusions The interchangeability of PRA measurement was unsatisfying. Harmonization on calibrator and ignoring blank were recommended. Unifying incubation strategy was unnecessary.

April 4, 2023

Salivary cortisol and cortisone in diagnosis of Cushing’s syndrome – a comparison of six different analytical methods

Nils Bäcklund, Göran Brattsand, Staffan Lundstedt, Elisabeth Aardal, Inga Bartuseviciene, Katarina Berinder, Charlotte Höybye, Pia Burman, Britt Edén Engström, Anders Isaksson, Anders Blomgren, Oskar Ragnarsson, Ulrika Rüetschi, Jeanette Wahlberg, Tommy Olsson, Per Dahlqvist

Page range: 1780-1791

Abstract

Objectives Salivary cortisol and cortisone at late night and after dexamethasone suppression test (DST) are increasingly used for screening of Cushing’s syndrome (CS). We aimed to establish reference intervals for salivary cortisol and cortisone with three liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques and for salivary cortisol with three immunoassays (IAs), and evaluate their diagnostic accuracy for CS. Methods Salivary samples at 08:00 h, 23:00 h and 08:00 h after a 1-mg DST were collected from a reference population (n=155) and patients with CS (n=22). Sample aliquots were analyzed by three LC-MS/MS and three IA methods. After establishing reference intervals, the upper reference limit (URL) for each method was used to calculate sensitivity and specificity for CS. Diagnostic accuracy was evaluated by comparing ROC curves. Results URLs for salivary cortisol at 23:00 h were similar for the LC-MS/MS methods (3.4–3.9 nmol/L), but varied between IAs: Roche (5.8 nmol/L), Salimetrics (4.3 nmol/L), Cisbio (21.6 nmol/L). Corresponding URLs after DST were 0.7–1.0, and 2.4, 4.0 and 5.4 nmol/L, respectively. Salivary cortisone URLs were 13.5–16.6 nmol/L at 23:00 h and 3.0–3.5 nmol/L at 08:00 h after DST. All methods had ROC AUCs ≥0.96. Conclusions We present robust reference intervals for salivary cortisol and cortisone at 08:00 h, 23:00 h and 08:00 h after DST for several clinically used methods. The similarities between LC-MS/MS methods allows for direct comparison of absolute values. Diagnostic accuracy for CS was high for all salivary cortisol and cortisone LC-MS/MS methods and salivary cortisol IAs evaluated.

April 4, 2023

Improved diagnostics of purine and pyrimidine metabolism disorders using LC-MS/MS and its clinical application

Alessio Cremonesi, David Meili, Anahita Rassi, Martin Poms, Barbara Tavazzi, Václava Škopová, Johannes Häberle, Marie Zikánová, Martin Hersberger

Page range: 1792-1801

Abstract

Objectives To develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify 41 different purine and pyrimidine (PuPy) metabolites in human urine to allow detection of most known disorders in this metabolic pathway and to determine reference intervals. Methods Urine samples were diluted with an aqueous buffer to minimize ion suppression. For detection and quantification, liquid chromatography was combined with electrospray ionization, tandem mass spectrometry and multiple reaction monitoring. Transitions and instrument settings were established to quantify 41 analytes and nine stable-isotope-labeled internal standards (IS). Results The established method is precise (intra-day CV: 1.4–6.3%; inter-day CV: 1.3–15.2%), accurate (95.2% external quality control results within ±2 SD and 99.0% within ±3 SD; analyte recoveries: 61–121%), sensitive and has a broad dynamic range to quantify normal and pathological metabolite concentrations within one run. All analytes except aminoimidazole ribonucleoside (AIr) are stable before, during and after sample preparation. Moreover, analytes are not affected by five cycles of freeze-thawing (variation: −5.6 to 7.4%), are stable in thymol (variation: −8.4 to 12.9%) and the lithogenic metabolites also in HCl conserved urine. Age-dependent reference intervals from 3,368 urine samples were determined and used to diagnose 11 new patients within 7 years (total performed tests: 4,206). Conclusions The presented method and reference intervals enable the quantification of 41 metabolites and the potential diagnosis of up to 25 disorders of PuPy metabolism.

May 1, 2023

Analytical evaluation of a GAD65 antibodies chemiluminescence immunoassay for CSF in neurological syndromes

Giulia Musso, Marco Zoccarato, Nicoletta Gallo, Andrea Padoan, Chiara Cosma, Luigi Zuliani, Piera De Gaspari, Elena Pegoraro, Mario Plebani, Daniela Basso

Page range: 1802-1807

Abstract

Objectives Antibodies against glutamic acid decarboxylase isoform 65 (GAD-Ab) have been found in different severe neurological conditions associated with altered synthesis of γ-aminobutyric acid (GABA). Serum GAD-Ab can be found in up to 90 % of patients with type 1 diabetes mellitus (T1DM), mostly at relatively low concentrations, while high concentrations of GAD-ab are thought to be more frequently associate to a neurological condition, with levels 100-folds higher than those found in T1DM. Although CSF testing is recommended when suspecting a GAD-associated neurological syndrome, no commercial immunoassay is validated for this use and no cut-off is internationally recognized to support the diagnosis. Methods In this study we validated CSF testing of GAD-Ab on an automated chemiluminescence (CLIA) immunoassay that had previously shown good agreement with ELISA on serum. Results We tested 43 CSF from patients with typical GAD-associated neurological disorders and patients with other neurological conditions, identifying a clinical cut-off of 18 kIU/L that discriminated GAD-disease with an area under the curve (AUC) of 0.921. CLIA showed good analytical performances on repeatability and recovery tests in CSF and confirmed an excellent agreement with ELISA. Conclusions GAD-Ab associated neurological disorders are rare but CSF testing for GAD-Ab is a common request for neurologists when suspecting an insidious autoimmune central nervous system disease. CLIA platforms are expected to be increasingly adopted in clinical laboratories due to their flexibility and reliability, therefore studies on decisional levels should be implemented for improving the interpretation and utilization of laboratory data.

Reference Values and Biological Variations

April 4, 2023

Evaluation of low-density lipoprotein cholesterol equations by cross-platform assessment of accuracy-based EQA data against SI-traceable reference value

Hwee Tong Tan, Sharon Yong, Hong Liu, Qinde Liu, Tang Lin Teo, Sunil Kumar Sethi

Page range: 1808-1819

Abstract

Objectives Low-density lipoprotein cholesterol (LDLC) is the primary cholesterol target for the diagnosis and treatment of cardiovascular disease (CVD). Although beta-quantitation (BQ) is the gold standard to determine LDLC levels accurately, many clinical laboratories apply the Friedewald equation to calculate LDLC. As LDLC is an important risk factor for CVD, we evaluated the accuracy of Friedewald and alternative equations (Martin/Hopkins and Sampson) for LDLC. Methods We calculated LDLC based on three equations (Friedewald, Martin/Hopkins and Sampson) using the total cholesterol (TC), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC) in commutable serum samples measured by clinical laboratories participating in the Health Sciences Authority (HSA) external quality assessment (EQA) programme over a 5 years period (number of datasets, n=345). LDLC calculated from the equations were comparatively evaluated against the reference values, determined from BQ-isotope dilution mass spectrometry (IDMS) with traceability to the International System of Units (SI). Results Among the three equations, Martin/Hopkins equation derived LDLC had the best linearity against direct measured (y=1.141x − 14.403; R 2 =0.8626) and traceable LDLC (y=1.1692x − 22.137; R 2 =0.9638). Martin/Hopkins equation (R 2 =0.9638) had the strongest R 2 in association with traceable LDLC compared with the Friedewald (R 2 =0.9262) and Sampson (R 2 =0.9447) equation. The discordance with traceable LDLC was the lowest in Martin/Hopkins (median=−0.725%, IQR=6.914%) as compared to Friedewald (median=−4.094%, IQR=10.305%) and Sampson equation (median=−1.389%, IQR=9.972%). Martin/Hopkins was found to result in the lowest number of misclassifications, whereas Friedewald had the most numbers of misclassification. Samples with high TG, low HDLC and high LDLC had no misclassification by Martin/Hopkins equation, but Friedewald equation resulted in ∼50% misclassification in these samples. Conclusions The Martin/Hopkins equation was found to achieve better agreement with the LDLC reference values as compared to Friedewald and Sampson equations, especially in samples with high TG and low HDLC. Martin/Hopkins derived LDLC also enabled a more accurate classification of LDLC levels.

April 11, 2023

Highly sensitive tandem mass spectrometric measurement of serum estradiol without derivatization and pediatric reference intervals in children and adolescents

Ashley Di Meo, Mehrdad Yazdanpanah, Victoria Higgins, Matthew Nichols, Mary Kathryn Bohn, Agnes Tan, Shazina Zainab, Lusia Sepiashvili, Khosrow Adeli

Page range: 1820-1828

Abstract

Objectives Monitoring estradiol (E2) is important for determining the onset of pubertal development as well as in the evaluation of girls with precocious puberty. However, E2 measurement remains an analytical challenge in children, who have lower circulating levels. We developed and evaluated a simple and sensitive LC-MS/MS procedure for serum E2 quantification in pediatric populations and established age- and sex-specific pediatric reference intervals. Methods Residual patient serum samples were used to evaluate the analytical performance of our in-house LC-MS/MS E2 assay. The evaluation included accuracy, precision, linearity, functional sensitivity (LLoQ), and method comparison. Age- and sex-specific pediatric E2 reference intervals were also established from a cohort of 405 healthy children (birth to 18 years) recruited with informed consent. Age- and sex-specific differences were assessed, and outliers were removed. Reference intervals were established using the robust method. Results The assay imprecision was <5.3 %. Assay linearity ranged from 13.7 to 1923.3 pmol/L. The LLoQ corresponding to a CV of 20 % was determined to be 8.9 pmol/L. Bland-Altman analysis revealed a mean bias of 29.3 pmol/L or 9.1 % between our LC-MS/MS E2 assay and an external reference laboratory measuring E2 by LC-MS/MS. Conclusions Our LC-MS/MS E2 assay shows acceptable accuracy, precision, functional sensitivity (LLoQ), and linearity for E2 quantification. Our LC-MS/MS E2 assay also showed good agreement with an external reference laboratory measuring E2 by LC-MS/MS. In addition, using CALIPER samples, we established robust age- and sex-specific pediatric E2 reference intervals to improve accuracy of test result interpretation and clinical decision making.

Cancer Diagnostics

March 31, 2023

Practical delta check limits for tumour markers in different clinical settings

Shinae Yu, Kyung-Hwa Shin, Sunghwan Shin, Hyeyoung Lee, Soo Jin Yoo, Kyung Ran Jun, Hangsik Shin, Sollip Kim

Page range: 1829-1840

Abstract

Objectives Few studies have reported on delta checks for tumour markers, even though these markers are often evaluated serially. Therefore, this study aimed to establish a practical delta check limit in different clinical settings for five tumour markers: alpha-fetoprotein, cancer antigen 19-9, cancer antigen 125, carcinoembryonic antigen, and prostate-specific antigen. Methods Pairs of patients’ results (current and previous) for five tumour markers between 2020 and 2021 were retrospectively collected from three university hospitals. The data were classified into three subgroups, namely: health check-up recipient (subgroup H), outpatient (subgroup O), and inpatient (subgroup I) clinics. The check limits of delta percent change (DPC), absolute DPC (absDPC), and reference change value (RCV) for each test were determined using the development set (the first 18 months, n=179,929) and then validated and simulated by applying the validation set (the last 6 months, n=66,332). Results The check limits of DPC and absDPC for most tests varied significantly among the subgroups. Likewise, the proportions of samples requiring further evaluation, calculated by excluding samples with both current and previous results within the reference intervals, were 0.2–2.9% (lower limit of DPC), 0.2–2.7% (upper limit of DPC), 0.3–5.6% (absDPC), and 0.8–35.3% (RCV 99.9% ). Furthermore, high negative predictive values >0.99 were observed in all subgroups in the in silico simulation. Conclusions Using real-world data, we found that DPC was the most appropriate delta-check method for tumour markers. Moreover, Delta-check limits for tumour markers should be applied based on clinical settings.

April 21, 2023

Comparison between free β subunit of human chorionic gonadotropin (hCG) and total hCG assays in adults with testicular cancer

Carel J. Pretorius, Urs Wilgen, Sandra Klingberg, Anna Zournazi, Linda Sanders, Jacobus P.J. Ungerer

Page range: 1841-1849

Abstract

Objectives We tested the hypothesis that the free-β subunit (βhCG) is diagnostically more sensitive with total hCG assays (hCGt) not detecting all tumours secreting βhCG. The effects of sex, age, and renal failure were investigated as secondary objectives. Methods We compared βhCG with hCGt in 204 testicular cancer patients (99 seminomas, 105 non-seminonatous germ cell tumours). The effects of sex and age were determined in 125 male and 138 female controls and that of renal failure was investigated in 119 haemodialysis patients. Biochemical assessment of gonadal status was performed with LH, FSH, oestradiol and testosterone. Results Discordant results were common with isolated increases of hCGt observed in 32 (15.7 %) and βhCG in 14 (6.9 %) patients. Primary hypogonadism was the most common cause of isolated hCGt increases. After therapeutic interventions βhCG decreased below its upper reference more rapidly than hCGt. We observed unequivocal false negative results in two patients with non-seminomatous germ cell tumours. Both occurred in patients with clinical tumour recurrences; in one instance we observed a false negative hCGt while in the second false negative βhCG’s were documented in serial samples. Conclusions The similar false negative rates did not support the hypothesis that βhCG will detect more patients with testicular cancer than hCGt. In contrast to hCGt, βhCG was unaffected by primary hypogonadism which is a predictably frequent complication in testicular cancer patients. We therefore recommend βhCG as the preferred biomarker in testicular cancer.

Hematology and Coagulation

April 21, 2023

Value of monocyte distribution width for predicting severe cholecystitis: a retrospective cohort study

Chih-Hao Kao, Yen-Hung Liu, Wei-Kung Chen, Fen-Wei Huang, Tai-Yi Hsu, Han-Tsung Cheng, Po-Ren Hsueh, Chiung-Tzu Hsiao, Shih-Yun Wu, Hong-Mo Shih

Page range: 1850-1857

Abstract

Objectives Acute cholecystitis is a gallbladder inflammation, and the Tokyo Guidelines 2018 (TG18) can be used to predict its presence and severity with high sensitivity and specificity. However, TG18 grading require the collection of excessive parameters. Monocyte distribution width (MDW) is a parameter used to detect sepsis early. Therefore, we investigated the correlation between MDW and cholecystitis severity. Methods We conducted a retrospective study of patients with cholecystitis admitted to our hospital from November 1, 2020, to August 31, 2021. The primary outcome was severe cholecystitis analyzed as a composite of intensive care unit (ICU) admission and mortality. The secondary outcomes were length of hospital stay, ICU stay, and TG18 grade. Results A total of 331 patients with cholecystitis were enrolled in this study. The average MDWs for TG18 grades 1, 2, and 3 were 20.21 ± 3.99, 20.34 ± 3.68, and 25.77 ± 6.61, respectively. For patients with severe cholecystitis, the average MDW was 25.42 ± 6.83. Using the Youden J statistic, we set a cutoff MDW of 21.6. Multivariate logistic regression revealed that patients with an MDW≥21.6 had a higher risk of severe cholecystitis (odds ratio=4.94; 95 % CI, 1.71–14.21; p=0.003). The Cox model revealed that patients with an MDW≥21.6 were more likely to have a prolonged hospital stay. Conclusions MDW is a reliable indicator of severe cholecystitis and prolonged length of stay. Additional MDW testing and a complete blood count may provide simple information for predicting severe cholecystitis early.

Open Access April 24, 2023

Performance of digital morphology analyzer Medica EasyCell assistant

Hanah Kim, Gun-Hyuk Lee, Sumi Yoon, Mina Hur, Hyeong Nyeon Kim, Mikyoung Park, Seung Wan Kim

Page range: 1858-1866

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Abstract

Objectives The EasyCell assistant (Medica, Bedford, MA, USA) is one of the state-of-the-art digital morphology analyzers. We explored the performance of EasyCell assistant in comparison with manual microscopic review and Pentra DX Nexus (Horiba ABX Diagnostics, Montpellier, France). Methods In a total of 225 samples (100 normal and 125 abnormal samples), white blood cell (WBC) differentials and platelet (PLT) count estimation by EasyCell assistant were compared with the results by manual microscopic review and Pentra DX Nexus. The manual microscopic review was performed according to the Clinical and Laboratory Standards Institute guidelines (H20-A2). Results WBC differentials between pre-classification by EasyCell assistant and manual counting showed moderate correlations for neutrophils (r=0.58), lymphocytes (r=0.69), and eosinophils (r=0.51) in all samples. After user verification, they showed mostly high to very high correlations for neutrophils (r=0.74), lymphocytes (r=0.78), eosinophils (r=0.88), and other cells (r=0.91). PLT count by EasyCell assistant highly correlated with that by Pentra DX Nexus (r=0.82). Conclusions The performance of EasyCell assistant for WBC differentials and PLT count seems to be acceptable even in abnormal samples with improvement after user verification. The EasyCell assistant, with its reliable performance on WBC differentials and PLT count, would help optimize the workflow of hematology laboratories with reduced workload of manual microscopic review.

Open Access May 5, 2023

Validation of non-invasive point of care blood content analysis using the TensorTip™ MTX device: a method comparison study

Sjoerd Servaas, Silke de Vreede, Ruben L. Smeets, An Stroobants, Lucas T. van Eijk, Ignacio Malagon, Cornelis Slagt

Page range: 1867-1874

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Abstract

Objectives The TensorTip™ MTX is a non-invasive device designed to determine several physiological parameters with additional analysis of haemoglobin, haematocrit and blood gas analysis by interpreting blood diffusion colour of the finger skin based on spectral analysis. The aim of our study was to investigate the accuracy and precision of the TensorTip MTX in a clinical setting in comparison with routine analysis of blood samples. Methods Forty-six patients, scheduled for elective surgery, were enrolled in this study. Placement of an arterial catheter had to be part of the standard of care. Measurements were performed during the perioperative period. The measurements obtained with the TensorTip MTX were compared with the results of routine analysis of the blood samples as a reference using correlation, Bland-Altman analysis and mountain plots. Results No significant correlation was present in the measurements. Measurement of haemoglobin with the TensorTip MTX had a mean bias of 0.4 mmol/L, haematocrit’s bias was 3.0 %. Bias of partial pressure of carbon dioxide and oxygen was 3.6 and 66.6 mmHg, respectively. Calculated percentage errors were 48.2 , 48.9, 39.9 and 109.0 %. Proportional bias was present in all Bland-Altman analyses. Less than 95 % of the differences fell within the pre-set limits of allowable error. Conclusions Non-invasive blood content analysis with the TensorTip MTX device is not equivalent to and did not correlate sufficiently with conventional laboratory analysis. None of the parameters measured showed results within the limits of allowable error. Therefore, the use of the TensorTip MTX is not recommended for perioperative care.

Infectious Diseases

Publicly Available April 21, 2023

Kinetics and ability of binding antibody and surrogate virus neutralization tests to predict neutralizing antibodies against the SARS-CoV-2 Omicron variant following BNT162b2 booster administration

Germain Simon, Julien Favresse, Constant Gillot, Mélanie Closset, Émilie Catry, Jean-Michel Dogné, Jonathan Douxfils, Grégoire Wieërs, Jean-Louis Bayart

Page range: 1875-1885

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Abstract

Objectives To assess the long-term humoral immunity induced by booster administration, as well as the ability of binding antibody and surrogate virus neutralization tests (sVNT) to predict neutralizing antibodies (NAbs) against the SARS-CoV-2 Omicron variant. Methods A total of 269 sera samples were analyzed from 64 healthcare workers who had received a homologous booster dose of BNT162b2. Neutralizing antibodies assessed by sVNT and anti-RBD IgG measured with the sCOVG assay (Siemens Healthineers ® ) were analyzed at five timepoints; before and up to 6 months following the booster. Antibody titers were correlated with neutralizing antibodies against the Omicron BA.1 variant obtained by pseudovirus neutralization test (pVNT) as a reference method. Results While Wild-type sVNT percentage of inhibition (POI) remained above 98.6% throughout the follow-up period after booster administration, anti-RBD IgG and NAbs assessed by Omicron BA.1 pVNT showed respectively a 3.4-fold and 13.3-fold decrease after 6 months compared to the peak reached at day 14. NAbs assessed by Omicron sVNT followed a steady decline until reaching a POI of 53.4%. Anti-RBD IgG and Omicron sVNT assays were strongly correlated (r=0.90) and performed similarly to predict the presence of neutralizing antibodies with Omicron pVNT (area under the ROC: 0.82 for both assays). In addition, new adapted cut-off values of anti-RBD IgG (>1,276 BAU/mL) and Omicron sVNT (POI>46.6%) were found to be better predictors of neutralizing activity. Conclusions This study showed a significant drop in humoral immunity 6 months after booster administration. Anti-RBD IgG and Omicron sVNT assays were highly correlated and could predict neutralizing activity with moderate performance.

Letters to the Editor

June 9, 2023

The first case of VEXAS syndrome in Austria

Bernhard Strasser, Alexander Haushofer

Page range: e187-e188

April 4, 2023

Acetylcholine receptor and muscle-specific tyrosine kinase antibodies detection: is it time for a change?

Danilo Villalta, Martina Fabris, Lorenzo Verriello, Francesca Grizzo, Emanuela Maria Mobilia, Anastasia Lechiara, Giampaola Pesce

Page range: e189-e191

April 25, 2023

Performance of the 2009 CKDEPI, 2021 CKDEPI, and EKFC equations among high-risk patients in Denmark

Morten Baltzer Houlind, Esben Iversen, Viktor Rotbain Curovic, Morten Buss Jørgensen, Aino Andersen, Finn Gustafsson, Lærke Marie Sidenius Nelson, Michael Perch, Morten Damgaard, Frederik Persson, Bo Feldt-Rasmussen, Ove Andersen, Trine Meldgaard Lund, Mads Hornum

Page range: e192-e195

April 11, 2023

Biotin interference in immunoassays: water under the bridge?

Loris Wauthier, Julien Cabo, Christine Eucher, Catherine Rosseels, Marc Elsen, Julien Favresse

Page range: e196-e199

April 18, 2023

The new synthetic benzimidazole opioid etonitazepipne: an emerging fatal harm and a challenge for laboratory medicine

Annagiulia Di Trana, Nunzia La Maida, Rino Froldi, Roberto Scendoni, Francesco Paolo Busardò, Simona Pichini

Page range: e200-e202

Open Access April 13, 2023

Unexplained increase of serum carcinoembryonic antigen: don’t forget the thyroid!

Filipe Miguel Montes de Jesus, Luca Giovanella

Page range: e203-e205

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Open Access April 24, 2023

Falsely elevated cortisol serum levels in preterm infants due to use of immunoassay

Michelle Romijn, Kirsten N.G. van de Weijer, Wes Onland, Joost Rotteveel, Anton H. van Kaam, Annemieke C. Heijboer, Martijn J.J. Finken

Page range: e206-e209

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May 1, 2023

Misdiagnosis of Hb Bart’s disease: prenatal screening and diagnosis of thalassemia in special population

Guichun Gan, Yan Li, Jinping Bai, Meiping Jiang, Lihong Zheng, Youqiong Li

Page range: e210-e213

About this journal

Objective
Clinical Chemistry and Laboratory Medicine (CCLM) publishes articles on novel teaching and training methods applicable to laboratory medicine. It is focused on basic and applied research and cutting-edge clinical laboratory medicine. CCLM is one of the leading journals in the field, with an impact factor over 8. All contributions submitted for publication in CCLM are single-blind peer reviewed by at least two experts in the field. CCLM is led by a multi-institutional editorial board. It is issued monthly, both in print and electronically. Letters to the Editor and Congress Abstracts are published online only.

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Topics

clinical biochemistry
clinical genomics and molecular biology
clinical haematology and coagulation
clinical immunology and autoimmunity
clinical microbiology
drug monitoring and analysis
evaluation of diagnostic biomarkers
disease-oriented topics (cardiovascular disease, cancer diagnostics, diabetes)
new reagents, instrumentation and technologies
new methodologies
reference materials and methods
reference values and decision limits
quality and safety in laboratory medicine
translational laboratory medicine
clinical metrology

Article formats
Research Articles, Reviews, Mini Reviews and Opinion Papers on all aspects of clinical chemistry and laboratory medicine, Guidelines and Recommendations, Point/Counterpoint Articles, Letters to the Editor, Editorials

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Volume 61 Issue 10

Issue of Clinical Chemistry and Laboratory Medicine (CCLM)

Frontmatter

Laboratory Medicine: from just testing to saving lives

Serum biomarkers of remodeling in severe asthma with fixed airway obstruction and the potential role of KL-6

Abstract

Safety monitoring of drug-induced muscle injury and rhabdomyolysis: a biomarker-guided approach for clinical practice and drug trials

Abstract

Concise review on the combined use of immunocapture, mass spectrometry and liquid chromatography for clinical applications

Abstract

Recommendation for the design of stability studies on clinical specimens

Abstract

Assessment of WHO 07/202 reference material and human serum pools for commutability and for the potential to reduce variability among soluble transferrin receptor assays

Abstract

veRification: an R Shiny application for laboratory method verification and validation

Abstract

Impact of storage temperature and time before analysis on electrolytes (Na+, K+, Ca2+), lactate, glucose, blood gases (pH, pO2, pCO2), tHb, O2Hb, COHb and MetHb results

Abstract

The stability of blood gases and CO-oximetry under slushed ice and room temperature conditions

Abstract

Elevated levels of renal function tests conferred increased risks of developing various pregnancy complications and adverse perinatal outcomes: insights from a population-based cohort study

Abstract

Poor comparability of plasma renin activity measurement in determining patient samples: the status quo and recommendations for harmonization

Abstract

Salivary cortisol and cortisone in diagnosis of Cushing’s syndrome – a comparison of six different analytical methods

Abstract

Improved diagnostics of purine and pyrimidine metabolism disorders using LC-MS/MS and its clinical application

Abstract

Analytical evaluation of a GAD65 antibodies chemiluminescence immunoassay for CSF in neurological syndromes

Abstract

Evaluation of low-density lipoprotein cholesterol equations by cross-platform assessment of accuracy-based EQA data against SI-traceable reference value

Abstract

Highly sensitive tandem mass spectrometric measurement of serum estradiol without derivatization and pediatric reference intervals in children and adolescents

Abstract

Practical delta check limits for tumour markers in different clinical settings

Abstract

Comparison between free β subunit of human chorionic gonadotropin (hCG) and total hCG assays in adults with testicular cancer

Abstract

Value of monocyte distribution width for predicting severe cholecystitis: a retrospective cohort study

Abstract

Performance of digital morphology analyzer Medica EasyCell assistant

Abstract

Validation of non-invasive point of care blood content analysis using the TensorTip™ MTX device: a method comparison study

Abstract

Kinetics and ability of binding antibody and surrogate virus neutralization tests to predict neutralizing antibodies against the SARS-CoV-2 Omicron variant following BNT162b2 booster administration

Abstract

The first case of VEXAS syndrome in Austria

Acetylcholine receptor and muscle-specific tyrosine kinase antibodies detection: is it time for a change?

Performance of the 2009 CKDEPI, 2021 CKDEPI, and EKFC equations among high-risk patients in Denmark

Biotin interference in immunoassays: water under the bridge?

The new synthetic benzimidazole opioid etonitazepipne: an emerging fatal harm and a challenge for laboratory medicine

Unexplained increase of serum carcinoembryonic antigen: don’t forget the thyroid!

Falsely elevated cortisol serum levels in preterm infants due to use of immunoassay

Misdiagnosis of Hb Bart’s disease: prenatal screening and diagnosis of thalassemia in special population

Impact of storage temperature and time before analysis on electrolytes (Na⁺, K⁺, Ca²⁺), lactate, glucose, blood gases (pH, pO₂, pCO₂), tHb, O₂Hb, COHb and MetHb results