Clinical Chemistry and Laboratory Medicine (CCLM)

Published by De Gruyter

Volume 40 Issue 6

Issue of Clinical Chemistry and Laboratory Medicine (CCLM)

Contents
Journal Overview

June 1, 2005

IFCC Primary Reference Procedures for the Measurement of Catalytic Concentrations of Enzymes – the New Concept

Klaus Lorentz

Page range: 549-549

June 1, 2005

Allele Frequency of the G→T Mutation of the Col1A1 Gene Analyzed by an ARMS-PCR in Osteoporotic Subjects with Femoral Neck Fractures

Lucio Montanaro, Carla Renata Arciola

Page range: 550-553

Abstract

The allele frequency of the G→T mutation of COL1A1 gene (collagen type I α 1 gene, GenBank accession n. AF017178) was analyzed by a new ARMS-PCR method in 240 osteoporotic subjects bearing a femoral neck fracture. The method is based on the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Normal and mutated alleles were detected by two PCRs, in which a common forward primer (positions 1307 to 1336 of the gene) and two reverse primers (positions 1566 to 1546), differing in the 3'-base (3'-C for the normal S allele and 3'-A for the mutated s allele) are used. In the SS condition, amplification occurs only in one of the two PCRs, and in the ss condition only in the other. In the Ss condition both reactions give a product. This ARMS-PCR method avoids the use of any restriction enzyme, as described by Grant and colleagues in a previously published method based on a mismatched reverse primer which introduced a restriction site in the T-substituted ( s ) allele and in a method recently proposed by Vinkanharju and co-workers. In a survey for COL1A1 polymorphism in 240 osteoporotic subjects with femur fractures, here presented, a frequency of 80.6% was found for the G allele and 19.4% for the T allele. There were 66.7% dominant SS subjects, 27.9% Ss heterozygotes and 5.4% ss recessive homozygotes.

June 1, 2005

Vitamin Supplementation Normalizes Total Plasma Homocysteine Concentration but Not Plasma Homocysteine Redox Status in Patients with Acute Coronary Syndromes and Hyperhomocysteinemia

Anders Andersson, Torfi Jonasson, Hans Öhlin, Arne Lindgren, Björn Hultberg

Page range: 554-558

Abstract

Despite the growing evidence that elevated total homocysteine (tHcy) in plasma is a cardiovascular risk factor, the mechanism underlying the vascular injury is still unknown. Studies are difficult due to the fact that little is known about the formation of different homocysteine species in vivo . In the present study we have investigated the different fractions of tHcy in 21 patients with acute coronary syndromes and elevated concentration of plasma tHcy. A subgroup of the patients (n=16) was investigated before and after a 3 months study period with or without vitamin supplementation (folic acid 5 mg, pyridoxine 40 mg and cyanocobalamin 1 mg once daily). A major finding is that these patients had a lowered ratio (0.95%) between the concentration of reduced homocysteine (HcyH) and tHcy compared to controls (1.38%). A low ratio HcyH/tHcy in plasma in combination with elevated plasma tHcy concentrations might reflect increased oxidative activity or decreased reducing capacity in plasma from the patients. Another main finding in the present study is that, although vitamin supplementation of these patients normalized plasma tHcy, the ratio between HcyH and tHcy did not normalize. Since substantial evidence indicates that progression of arteriosclerosis is related to enhanced oxidant activity, the premature vascular disease associated with increased plasma tHcy concentration might be due to increased oxidative activity and the elevated plasma tHcy concentration may only reflect the increased oxidative stress.

June 1, 2005

Mutation Analysis of the MPZ and PMP22 Genes in Croatian Patients

Branca Grškovic, Goran Ferenčak, Ana Stavljenić Rukavina, Monika Karija, Ivana Furač, Milovan Kubat

Page range: 559-562

Abstract

We used single-strand conformation polymorphism analysis for mutational screening in two candidate genes, MPZ and PMP22 , which have an important role in the pathogenesis of Charcot-Marie-Tooth disease (CMT) and related peripheral neuropathies. A novel Ser8Ser polymorphism was found in exon 1 of the MPZ gene in two heterozygous subjects, in a father with mild CMT2 phenotype and his daughter with normal clinical data. Thr118Met polymorphism was found in exon 5 of the PMP22 gene. The patient heterozygous for 118Met allele had CMT1 disease. We can conclude that the occurrence of the 118Met allele does not usually cause CMT1 and that it is not a clinically relevant disease marker.

June 1, 2005

Dynamic Equilibrium between Protein S and C4b Binding Protein Is Important for Accurate Determination of Free Protein S Antigen

Tomohide Tsuda, Hiroko Tsuda, Hajime Yoshimura, Naotaka Hamasaki

Page range: 563-567

Abstract

Protein S in circulation is in a dynamic equilibrium with C4b binding protein (C4bBP), thus affecting the measurement of free protein S antigen. We addressed the issue of overestimation of the free protein S concentration with current immunoassays due to the dynamic equilibrium and propose a new method for its accurate determination. Our assay system was tested at different reaction temperatures using purified free protein S, protein S-C4bBP complexes, plasma samples, and a commercially available free protein S assay kit. At a reaction temperature of 37°C, the free protein S fraction increased from 0.5 ng/ml (at 4°C) to 7.8 ng/ml, and from 4.5 ng/ml (at 4°C) to 56 ng/ml when the concentration of the assayed protein S-C4bBP complexes was 20 ng/ml and 200 ng/ml, respectively. In plasma samples, free protein S levels were approximately 0.8 μg/ml and 6 μg/ml higher at 25°C and 37°C, respectively compared to measurements at 4°C. Measurements of free protein S in plasma using a commercially available assay kit were approximately 0.6 μg/ml higher at 25°C than measurements performed at 4°C. Dynamic equilibrium between protein S and C4bBP affects the measurement of free protein S antigen. Measurement of free protein S antigen should be performed under conditions where protein S is not dissociated from protein S-C4bBP complexes, as exemplified by assay at low temperature (4°C).

June 1, 2005

Immunoassay of Anti-Thyroid Autoantibodies: High Analytical Variability in Second Generation Methods

Renato Tozzoli, Nicola Bizzaro, Elio Tonutti, Marco Pradella, Fabio Manoni, Danilo Vilalta, Danila Bassetti, Anna Piazza, Paolo Rizzotti

Page range: 568-573

Abstract

The use of highly sensitive immunometric methods in clinical laboratories to assay anti-thyroid antibodies has progressively expanded in recent years but it is not known whether the new techniques have improved the analytical variability connected with the preceding methodologies. The Italian Society of Laboratory Medicine Study Group on Autoimmune Diseases conducted a collaborative study with the biomedical industry to evaluate the degree of standardization of the new analytical procedures. Twelve companies agreed to participate in the study on the search for anti-thyroglobulin (anti-Tg) and anti-thyroperoxidase (anti-TPO) antibodies in nine sera from patients with autoimmune thyroiditis, and in six sera from patients with non-autoimmune thyroid disease; ten immunometric and three immunofluorescence methods were employed. Agreement of qualitative results was close to 90% for anti-Tg and 97% for anti-TPO, with no important differences between the methods; variability of the quantitative results, expressed as CV% of absolute (in IU/ml) and relative (in cut-off concentration multiples) values was 93.9% and 102.3%, respectively, for anti-Tg, and 75.5% and 62.9%, respectively, for anti-TPO. These findings show that despite the progressive improvement in the analytical techniques, the variability between methods for the assay of anti-Tg and anti-TPO is still unexpectedly high, and probably due to several factors such as uncertainty in defining the positive cutoff concentration, absence of adequate international reference preparations, modality of autoantigen purification, and analytical variability in the assay procedures.

June 1, 2005

The Measurement of Insulin-like Growth Factor-I (IGF-1) Concentration in Random Urine Samples

Elio F. De Palo, Rosalba Gatti, Federica Lancerin, Enrico Cappellin, Alessandro Sartorio, Paolo Spinella

Page range: 574-578

Abstract

The aim of the present study was to assess a suitable expression of the urinary concentration of a protein/peptide hormone such as insulin-like growth factor-I (IGF-I), measured in the urine of healthy individuals when the specimen collection is executed randomly. One hundred and twenty male subjects were divided by age into four groups, namely healthy sedentary young (SYA) and older (SOA) adults, older (OC) and young (YC) children. In a single urine specimen, randomly collected during the morning from each individual, total urinary IGF-I was measured by immunoradiometric method, and urinary creatinine (uCr) and total proteins (utPr) were measured by capillary electrophoresis and spectrophotometric methods, respectively. The urinary IGF-I concentrations were not significantly different in all groups investigated and they were (mean±SD): 82.7±82.8 ng/l, 103.5±83.3 ng/l, 80.4±64.4 ng/l in OC, SYA and SOA, respectively; only in the YC group there was a tendency to higher values (125.2±93.2 ng/l) compared with the other groups. utPr ranged from 26 to 40 mg/l and did not demonstrate significant differences between groups. The urinary IGF-I correlated with uCr and utPr, and statistical significance was observed in all measurements. The measurement of urinary IGF-I in random urine and its ratio to utPr is an innovative, useful way of investigation of urinary protein/peptide hormones.

June 1, 2005

Urinary Bikunin Determination Provides Insight into Proteinase/Proteinase Inhibitor Imbalance in Patients with Inflammatory Diseases

Charlotte Mizon, Frank Piva, Viviane Queyrel, Malika Balduyck, Eric Hachulla, Jacques Mizon

Page range: 579-586

Abstract

Bikunin (BK) is a Künitz-type proteinase inhibitor responsible for most of the antitryptic activity of urine and so is known as the urinary trypsin inhibitor. As its excretion increases in inflammatory conditions, it is often considered to be a positive acute phase protein (APP). However, the gene for BK is downregulated in inflammation. In human plasma the major part of BK is covalently linked through a glycosaminoglycan chain to one or two homologous peptide heavy chains, thus forming high molecular weight proteinase inhibitors called preαinhibitor (PαI) and inter-α-inhibitor (IαI), respectively. The C -terminal parts of these heavy chains are very sensitive to proteolysis. Neutrophil proteinases in particular are able to release from IαI and PαI BK (M r about 25000) which retains its antitryptic activity and is quickly excreted in urine. It was therefore an early supposition that the higher urinary excretion of BK occurring during inflammatory diseases should be, at least in some respect, related to a partial proteolysis of IαI and PαI. In this study we observed that BK, determined as antitryptic activity, was clearly increased in urine from 35 patients with inflammatory diseases varying in origin and severity (76.5±75.5 IU/g vs. reference value <10 IU/g creatinine). This increase seems mainly to be associated with polymorphonuclear leukocyte activation, monitored by human leukocyte elastase (HLE) determination rather than with the acute phase response assessed by C-reactive protein (CRP) measurement. For all the patients we found that the urinary levels of BK and serum concentration of intact IαI correlated inversely (r=−0.36; p=0.03), in agreement with the presumed precursorproduct relationship linking IαI and BK. We also proved that urinary BK was significantly higher, and serum IαI was significantly lower, in samples with plasma HLE values above the reference: 90 μg/l. Taken together, our results demonstrate that BK, the urinary excretion of which is increased in inflammatory conditions, originates, at least partly, from IαI and PαI by proteolytic cleavage. Consequently, urinary BK determination provides information on the severity of systemic proteolysis occurring in inflammation. We also demonstrated that during inflammatory diseases IαI and PαI concentrations in serum are dependent on their increased utilization as well as on the regulation of their biosynthesis.

June 1, 2005

Breath Markers and Soluble Lipid Peroxidation Markers in Critically Ill Patients

Joachim Scholpp, Jochen K. Schubert, Wolfram Miekisch, Klaus Geiger

Page range: 587-594

Abstract

Free radical-mediated inflammatory processes account for a great portion of morbidity and mortality in critically ill patients. The purpose of this study was to determine two plasma peroxidation markers and three volatile markers related to lipid peroxidation, metabolic activity and cholesterol metabolism, and to explore relationships between the different markers and patients' clinical status. Substances were analyzed in whole blood and in exhaled air in patients with head injury, acute respiratory distress syndrome (ARDS) and in those being at risk of developing ARDS. These results were compared with the baseline measurements in healthy individuals. Additionally, patients were assessed according to their inflammatory status. Concentrations of malondialdehyde and thiobarbituric acid-reactive substances in plasma as well as pentane concentrations in breath increased with increasing inflammatory status. Although these compounds are generated through peroxidation of fatty acids, concentrations of these markers were significantly different in patient groups. Isoprene concentrations were lowest in the ARDS group. Acetone concentrations were not different between patient groups. We conclude that for the assessment of lipid peroxidation and other inflammatory reactions a set of parameters has to be defined. More detailed insights into inflammatory processes can be obtained when the volatile markers and the serum markers are considered together.

June 1, 2005

Comparison of Laser-Probe and Photometric Determination of the Urinary Crystallization Risk of Calcium Oxalate

Norbert Laube, Stefan Hergarten, Albrecht Hesse

Page range: 595-599

Abstract

A variety of equipment is used for the observation of precipitation processes which occur in urinary samples. The Bonn-Risk-Index, a measure of the calcium oxalate crystallization risk of human urine, has been developed with the use of an in-line laser-probe gauge. For basic research or in clinical laboratories, however, this instrument, which fulfills industrial requirements for the evaluation of particle size distributions, is not widely available. The evaluation of an alternative method to determine the Bonn-Risk-Index based on a more commonly available apparatus would therefore be useful. In vitro crystallization experiments with 124 native urine samples from stone-forming and non-stone forming individuals were performed in order to determine their crystallization risk according to the Bonn-Risk-Index approach. The onset of an induced urinary crystallization was detected by simultaneous sample monitoring with an in-line laser-probe and a conventional dip-in photometer. A decrease of the sample's relative light transmissivity from initially 100% to 98% was assumed to be a reliable photometer-based criterion to indicate that crystallization actually began. The laser-probe signal was set as the reference measure. Linear regression analysis of the results of the laser-probe and the photometer-based Bonn-Risk-Index determinations reveals a significant and close correlation between the two measures. Method comparison by statistical evaluation shows i) that no significant deviation from linearity exists and ii) that both methods are statistically identical. The differences in the results are small enough to be confident that the photometer can be used in place of the laser-probe for clinical purposes. The photometer is a reliable, easy-to-use and cost-effective method for the determination of a triggered crystallization event in a urine sample. The assumed 98% criterion allows the determination of the Bonn-Risk-Index with adequate accuracy.

June 1, 2005

Comparison of First Trimester, Second Trimester and Integrated Downs Syndrome Screening Results in Unaffected Pregnancies

Silvana Canini, Federico Prefumo, Luciano Famularo, Pier Luigi Venturini, Valter Palazzese, Pierangela De Biasio

Page range: 600-603

Abstract

Our aim was to compare the results of first trimester combined test, second trimester triple test, and integrated test in the same pregnant population. We retrospectively studied 927 women, all giving birth to an unaffected baby except for two cases of Down's syndrome. The women underwent a nuchal translucency ultrasound measurement and a blood sampling for pregnancy-associated plasma protein A and free β-hCG subunit (free total chorionic gonadotropin subunit) assay in the first trimester of pregnancy. A second trimester biochemical screening (α-fetoprotein, unconjugated oestriol and total hCG) was performed later. The correlations between each pair of markers and between each marker level and maternal age were calculated. No marker showed significant correlation with any other or with maternal age, with the obvious exception of free β-hCG subunit and total hCG. The false-positive rate (cut-off level: 1 in 350 at term) was 1.5% for the first trimester test, 3.6% for the second trimester test and 0.54% for the integrated test. In 10/14 pregnancies, the increased risk in the first trimester was not confirmed neither in the second trimester nor by the integrated test. In 29/33 women with an increased risk in the second trimester, the first trimester and the integrated test results were discordant. The absence of correlation among different marker levels suggests that the information supplied by the first and second trimester tests is different. Integrating first and second trimester markers in a single test could pose the ethical problem of withholding first trimester results and thus denying the possible advantages of an earlier pregnancy termination.

June 1, 2005

Anti-Phospholipid Antibodies in Diabetes Mellitus

Henri Gin, Vincent Vergnot, Vicky Diakou, Anne-Marie Perret, Jerôme Poix, Claude Cassagne, Lilly Maneta-Peyret

Page range: 604-608

Abstract

The presence of autoantibodies to phospholipids may be associated with various pathological disorders; diabetes could be one of them because of the changes occurring in lipid metabolism but there are only few reports examining this question, and they are not always leading to the same conclusions because of the differences in the procedures or in the phospholipids tested. We carried out a systematic comparative study of diabetic serum antibody binding to all phospholipids, anionic and zwitterionic, by a quantitative ELISA. The implication of the hydrophobic moiety of the lipids was also studied: the presence of autoantibodies to the fatty acyl chains was investigated. Our results show the presence of anti-phospholipid antibodies in diabetic sera, particularly anti-phosphatidylinositol and anti-phosphatidylcholine which have never been tested before, and appear to be associated with macroangiopathic complications. The antigenic epitopes are mainly the polar heads as no antibody binding to the hydrophobic moiety was observed. We discuss the relation of those antibodies to the angiopathic complications and to the direct effects of hyperglycemia on lipid antigenicity.

June 1, 2005

Alteration of Serum Enzymes in Primary Hypothyroidism

Biswajit Saha, Chittaranjan Maity

Page range: 609-611

Abstract

In order to study the relationships between serum enzymes and the degree of hypothyroidism, 114 patients with primary hypothyroidism aged from 7 to 65 years were investigated. Forty one percent of patients exhibited normal levels of serum enzymes, while 59% had high levels either alone or in combination. The frequency of enzyme elevation was as follows: creatine kinase: 37%, aspartate aminotransferase: 35%, alanine aminotransferase: 29%, amylase: 15%, alkaline phosphatase: 3%. No significant correlation between thyroid stimulating hormone and serum enzyme levels was observed. This was due to highly variable release of enzymes from cells resulting presumably from individual metabolic set-point. Replacement therapy with thyroxine resulted in remarkable lowering of creatine kinase not only from high level to normal as early as 3 weeks even before normalization of thyroid stimulating hormone, but also from high normal to low normal level. The elevation of amylase and its response to thyroxine is being reported for the first time.

June 1, 2005

The Changes of Superoxide Dismutase, Catalase and Glutathione Peroxidase Activities in Erythrocytes of Active and Passive Smokers

Leyla Yildiz, Neslihan Kayaoğlu, Hülya Aksoy

Page range: 612-615

Abstract

Cigarette smoking has been implicated in the pathogenesis of ischemic heart disease, emphysema, obstructive lung disease and neoplastic disorders. More than 1000 constituents of smoke, including many oxidants, pro-oxidants, free radicals and reducing agents, have been identified. The activities of erythrocyte superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), which are the important components of antioxidant defense system, were measured in 100 healthy volunteers. This study included heavy smokers (consuming cigarettes ≥20 per day; n=30, group I), light smokers (consuming cigarettes< 20 per day; n=30, group II), passive smokers (exposed to cigarette smoke in the indoor environment; n=20, group III), and non-smokers (n=20, the control group). While activities of SOD and CAT in erythrocytes were significantly lower in groups I, II and III than in the control group (p<0.01 for all), mean erythrocyte GSH-Px activity in group III was higher than that in groups I, II and in controls. These results suggest that the increased oxidative stress occurs in smokers, owing to the free radicals present in smoke. It might cause a decrease in antioxidant enzyme activities and oxidant/antioxidant imbalance. We also observed that passive smokers were affected by the environmental smoke to the same extent as active smokers.

June 1, 2005

Internal Quality Control System for Non-Stationary, Non-Ergodic Analytical Processes Based upon Exponentially Weighted Estimation of Process Means and Process Standard Deviation

Rob T.P. Jansen, Mark Laeven, Wim Kardol

Page range: 616-624

Abstract

The analytical processes in clinical laboratories should be considered to be non-stationary, non-ergodic and probably non-stochastic processes. Both the process mean and the process standard deviation vary. The variation can be different at different levels of concentration. This behavior is shown in five examples of different analytical systems: alkaline phosphatase on the Hitachi 911 analyzer (Roche), vitamin B 12 on the Access analyzer (Beckman), prothrombin time and activated partial thromboplastin time on the STA Compact analyzer (Roche) and pO 2 on the ABL 520 analyzer (Radiometer). A model is proposed to assess the status of a process. An exponentially weighted moving average and standard deviation was used to estimate process mean and standard deviation. Process means were estimated overall and for each control level. The process standard deviation was estimated in terms of withinrun standard deviation. Limits were defined in accordance with state of the art-or biological variancederived cut-offs. The examples given are real, not simulated, data. Individual control sample results were normalized to a target value and target standard deviation. The normalized values were used in the exponentially weighted algorithm. The weighting factor was based on a process time constant, which was estimated from the period between two calibration or maintenance procedures. The proposed system was compared with Westgard rules. The Westgard rules perform well, despite the underlying presumption of ergodicity. This is mainly caused by the introduction of the starting rule of 1 2s , which proves essential to prevent a large number of rule violations. The probability of reporting a test result with an analytical error that exceeds the total allowable error was calculated for the proposed system as well as for the Westgard rules. The proposed method performed better. The proposed algorithm was implemented in a computer program running on computers to which the analyzers were linked on-line. Each result was evaluated on-line, and a limit violation was immediately reported. The system has performed satisfactorily in our laboratory for ten analyzers for over 1 year.

June 1, 2005

Evaluation of Commutability of Control Materials

Emmanuel Brion, Jean-Marc Lessinger, Nicholas Gould, Jacky Leyendecker, Georges Férard

Page range: 625-630

Abstract

The commutability of 13 control materials was evaluated by performing parallel measurements on two different analysers: a Synchron CX-5 Delta from Beckman-Coulter and a Vitros 950 from Ortho-Clinical Diagnostics. Twenty three clinical chemistry analytes (substrates, electrolytes and enzymatic activities) were determined in plasma from 15 different patients in order to define intermethod relationship for each analyte. The relationship observed for each control material was compared to those obtained for patients' specimens. The results show that commutability depends both on the tested analyte and on the control material. No totally commutable material has been found for the whole set of tested parameters. Most control materials were commutable for inorganic phosphate, glucose, chloride, triglycerides, alanine aminotransferase, amylase and γ-glutamyltransferase, but less than a quarter of control materials were commutable for sodium, calcium, creatinine, alkaline phosphatase and lipase. Seven materials were commutable for more than half of the analytes, whereas five control materials were commutable for less than a quarter of these analytes. We propose to verify the commutability of materials before their use in an external quality control assessement.

June 1, 2005

IFCC Primary Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes at 37°C. Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes

L. Siekmann, R. Bonora, C. A. Burtis, F. Ceriotti, P. Clerc-Renaud, G. Férard, C. A. Ferrero, J.-C. Forest, P. F.H. Franck, F.-J. Gella, W. Hoelzel, P. J. Jørgensen, T. Kanno, A. Kessner, R. Klauke, N. Kristiansen, J.-M. Lessinger, T. P. J. Linsinger

Page range: 631-634

Abstract

This paper is the first in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C and with the certification of reference preparations. Other parts deal with: Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of γ-Glutamyltransferase; Part 7. Certification of Four Reference Materials for the Determination of Enzymatic Activity of γ-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37°C. A document describing the determination of preliminary reference values is also in preparation.

June 1, 2005

IFCC Primary Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes at 37°C. Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase

G. Schumann, R. Bonora, F. Ceriotti, P. Clerc-Renaud, C. A. Ferrero, G. Férard, P. F. H. Franck, F.-J. Gella, W. Hoelzel, P. J. Jørgensen, T. Kanno, A. Kessner, R. Klauke, N. Kristiansen, J.-M. Lessinger, T. P.J. Linsinger, H. Misaki, M. Panteghini

Page range: 635-642

Abstract

This paper is the second in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C and the certification of reference preparations. Other parts deal with: Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of γ-Glutamyltransferase; Part 7. Certification of Four Reference Materials for the Determination of Enzymatic Activity of γ-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37°C. A document describing the determination of preliminary reference values is also in preparation. The procedure described here is deduced from the previously described 30°C IFCC reference method (1). Differences are tabulated and commented on in Appendix 3.

June 1, 2005

IFCC Primary Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes at 37°C. Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase

Page range: 643-648

Abstract

This paper is the third in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37°C and the certification of reference preparations. Other parts deal with: Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes; Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of γ -glutamyltransferase; Part 7. Certification of Four Reference Materials for the Determination of Enzymatic Activity of γ-Glu tamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37°C. A document describing the determination of preliminary upper reference limits is also in preparation. The procedure described here is deduced from the previously described 30°C IFCC reference method (1). Differences are tabulated and commented on in Appendix 1. Clin Chem Lab Med 2002; 40(6):643648

July 27, 2005

Meetings and Awards

Page range: 649-652

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

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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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