Accessible Published by De Gruyter June 5, 2020

Exact time of venous blood sample collection – an unresolved issue, on behalf of the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for Preanalytical Phase (WG-PRE)

Alexander von Meyer, Giuseppe Lippi, Ana-Maria Simundic and Janne Cadamuro ORCID logo

Abstract

Objectives

An accurate knowledge of blood collection times is crucial for verifying the stability of laboratory analytes. We therefore aimed to (i) assess if and how this information is collected throughout Europe and (ii) provide a list of potentially available solutions.

Methods

A survey was issued by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group on Preanalytical Phase (WG-PRE) in 2017, aiming to collect data on preanalytical process management, including sampling time documentation, in European laboratories. A preceding pilot survey was disseminated in Austria in 2016. Additionally, preanalytical experts were surveyed on their local setting on this topic. Finally, the current scientific literature was reviewed on established possibilities of sampling time collection.

Results

A total number of 85 responses was collected from the pilot survey, whilst 1347 responses from 37 European countries were obtained from the final survey. A minority (i.e. ~13%) of responders to the latter declared they are unaware of the exact sampling time. The corresponding rate in Austria was ~70% in the pilot and ~30% in the final survey, respectively. Answers from 17 preanalytical experts from 16 countries revealed that sampling time collection seems to be better documented for out- than for in-patients. Eight different solutions for sample time documentation are presented.

Conclusions

The sample collection time seems to be documented very heterogeneously across Europe, or not at all. Here we provide some solutions to this issue and believe that laboratories should urgently aim to implement one of these.

Introduction

The quality of pre- and post-analytical phases in laboratory medicine is, amongst other aspects, guaranteed by maintaining specified time intervals, such as the maximum allowable period between sample collection and centrifugation (when needed) or analysis, duration of transportation, storage time and so forth. An accurate definition of these time intervals is crucial for assuring the analytical stability of biospecimens, providing information allowing the laboratory staff to determine how much the result has varied from the true value and whether this bias is analytically or clinically acceptable. National and international standards mandate most laboratories to track the sample journey, including the time interval between collection and first check-in in the laboratory [1]. The application of accurate storage limits after analysis is also necessary for preventing deterioration of many analytes in biological samples. Many approaches are already existing or underway for this purpose. Moreover, some regularly updated databases have been established on sample stability [2], [3]. The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group on Preanalytical Phase (WG-PRE) is also currently establishing a standardized checklist for stability studies in order to make data comparable [4]. This information is necessary in all modern laboratory services, for comparing local practices of sample handing with clearly established limits.

Figure 1: EFLM survey – Answers to the question “Are the exact date and time of blood collection provided with the sample?” in regards to the accreditation/certification status of the responding laboratory.
Numbers in white at the bottom of the columns represent the total number of responses.

Figure 1:

EFLM survey – Answers to the question “Are the exact date and time of blood collection provided with the sample?” in regards to the accreditation/certification status of the responding laboratory.

Numbers in white at the bottom of the columns represent the total number of responses.

Ideally, tracking a sample journey requires collection of accurate information on the time elapsed between collection of samples and their delivery to the testing point or the point of stabilization, which is very often a centralized clinical laboratory. The time of delivery can be easily monitored, as sample check-in timepoints are recorded by the vast majority of laboratory information systems (LISs). However, there is widespread perception that the quality of information on sample collection time, provided by the staff in charge of ordering the test and/or drawing blood, may be largely unreliable [5], [6]. This is of outmost significance if one considers that the stability of many analytes can only be safely guaranteed when all respective timepoints are monitored. The current scientific literature emphasizes that accurate registration of collection time is necessary for deciding as to whether some tests shall be performed or not (e.g. plasma glucose, hormones, therapeutic drug monitoring). Many test reference intervals, as well as results of therapeutic drug monitoring, are strongly dependent on the sampling time [5], [7], [8], [9]. Therefore, major efforts should be made to improve the quality of this information, thus developing reliable tools for improving current practices, especially in those centers where this aspect may be partly (or completely) overlooked or underestimated. Hence, this study is aimed to present the unpublished part of the results of a previous EFLM survey [10], [11], and provide an overview and discussion on possible solutions to better address the issue of sampling time registration.

Materials and methods

The results discussed in this paper are a part of a larger survey, carried out by the EFLM WG-PRE between October 1st and November 30th 2017 [10], [11]. The study aimed to investigate how European laboratories are currently dealing with preanalytical sampling handling in general, as well as with hemolysis, icterus and lipemia interference, in particular.

Before widespread dissemination across European laboratories, the survey was piloted in Austria from March 9th until April 17th, 2016. The pilot survey was disseminated among 359 Austrian laboratories by the national external quality assessment (EQA) provider (ÖQUASTA), using an online survey tool (Surveymonkey, San Mateo, CA, USA). Results of this survey were not published, as they only served as a basis for defining a final European survey. Among other interrogations regarding preanalytical topics, this pilot survey contained the following question: “Do you know when blood was collected?” (answer options were “Yes”, “No” and “Other”). Free text responses to the option “other” were categorized.

Based on these answers, the corresponding question in the final EFLM survey was modified as follows: “Are the exact date and time of blood collection provided with the sample?” (answers options were “Yes, for all samples”, “Yes, for most samples”, “Yes, for some samples”, “No (e.g. only the time of order placement is provided)” and “We do not collect blood from in-/out-patients”). Answers had to be provided for both inpatients and outpatients (including primary care) separately, when appropriate (matrix question). Answers were evaluated overall as well as country specific, using IBM SPSS Statistics V.24 (IBM, Armonk, NY, USA).

To obtain further information on this matter in different European countries, another brief survey was disseminated by email in January 2019 among the national representatives of the EFLM WG-PRE and some expert consultants of this Working group (WG). All the members of this WG are experts on preanalytical issues and therefore qualified to provide professional feedback on this specific topic. The survey was carried out as an open question, asking for brief description on sampling time registration and documentation at their local facilities. All free text answers were summarized in a table for comparing the different situation (Tables 1 and 2). In- and outpatients were separated, thus avoiding biases due to differences in operational processes between these collectives. In a hospital setting often two different forms of organization exist, collection by specialized phlebotomist or sampling by general nurses or doctors. Both situations can exist in the same hospital and are therefore assessed separately. After the responses were analyzed and incorporated into an explanatory table, the draft was sent back to participants, so that they could approve the trueness and correctness in interpretation of the free text answers.

Table 1:

Results from EFLM Pilot-Survey among Austrian laboratories.

n %
Yes 19 22.4
Partly 6 7.1
No (e.g. only the time of order placement is provided) 59 69.4
No samples sent from external sources 1 1.2
Total 85

Table 2:

Results from EFLM Survey among 37 European countries.

All participants
Austrian participants
In-patients
Out-patients
In-patients
Out-patients
n % n % n % n %
Yes, for all samples 654 48.6 488 36.2 26 38.8 16 23.9
Yes, for most samples 349 25.9 437 32.4 13 19.4 12 17.9
Yes, for some samples 108 8.0 149 11.1 6 9.0 11 16.4
No (e.g. only the time of order placement is provided) 169 12.5 187 13.9 20 29.9 20 29.9
We don’t serve in/out-patients 67 5.0 86 6.4 2 3.0 8 11.9
Total 1347 1347 67 97.0 67 88.1

Aiming to provide information on possible methods of sampling time documentation, including their benefits, limitations and requirements, all authors reviewed current literature, manufacturer information or collected information from personal experience or experiences from colleagues and bundled results in a structured manner.

Results

Pilot survey carried out in Austria in 2016

A total of 101/359 replies (response rate, 28.1%) were received, 88 of which answered to the question on time of blood collection. Three answers were left blank and had to be excluded. Replies of the remaining 85 answers regarding the time of blood collection are shown in Table 1.

Results of EFLM survey in 2017

A total number of 1416 responses from 45 different countries could be collected. After eliminating responses from laboratories which did not handle blood samples or from non-EFLM member states, 1347 responses from 37 European countries were further evaluated. All participants answered the question concerning sampling time, 67 of which were from Austria.

The main results of the EFLM survey on collection time are shown in Table 2. About 70% of participating laboratories of the pilot study stated that they are not informed on the exact blood collection time upon receiving samples. This number decreased to approximately 30% when Austrian responders answered the respective question on the final European survey.

Results of survey among WG-PRE members in 2018

Overall, 17 preanalytical experts of 16 different countries provided detailed information on their healthcare setting concerning sampling time of in- and outpatients for their health care setting. Results are shown in Table 3.

Table 3:

Results from survey among EFLM WG-PRE members.

Country Inpatients
Outpatients
Phlebotomist
Other staff
All staff
Special device Documentation in HIS/LIS/Ordering system Time quality Special device Documentation in HIS/LIS/Ordering system Time quality Special device Documentation in HIS/LIS/Ordering system Time quality
Germany No Variable Bad No Variablea Bad n/a n/a n/a
Austria n/a n/a n/a No No Bad no Good Good
Italy n/a n/a n/a No Variable Bad yes Excellent Excellent
Croatia n/a n/a n/a No Variable Bad Yes Good Good
Spain no no bad No No Bad No No Bad
Spain [2] n/a n/a n/a No Variable Bad No Variable Variableb
UK No Good Good No Variable Variable No Variable Bad
Denmark Yes Excellent Excellent No Variablea Good No Good Good
Sweden No Excellent Excellent No Excellent Excellent No Excellent Excellent
Turkey n/a n/a n/a Yes Excellent Good Yes Excellent Good
Belgium n/a n/a n/a No Good Good No Excellent Excellent
Russia No No Bad No Variable Bad No Good Good
US No Excellent Excellent No Good Variable No Excellent Excellent
Portugal n/a n/a n/a No Variablea Good Yes Excellent Good
Serbia n/a n/a n/a No No Bad No Good Good
Ireland No Good Good No Good Good No No Bad
Norway No Excellent Good No Excellent Good No Good Good

  1. Personal experience of the WG-PRE members in their own hospitals. Special device: Are solutions other than paper-based or CPOE systems used?; Documentation in hospital information system (HIS)/laboratory information system (LIS): Rating of the functionality to communicate sampling time; Rating categories were: no (functionality not available); variable (available at some sites); good (available almost everywhere) and excellent (everywhere available). Time quality: Rating of the documentation quality; Rating categories were: bad; variable; good and excellent. aOften pre-entered, meaning written a priori in the LIS, but not necessarily adjusted according to the actual time of sampling; bhospital unit – perfect, primary care unit – weak.

Discussion

According to the results of our surveys, documentation on accurate sampling time appears to be handled rather heterogeneously throughout Europe, and shall still be considered an unresolved issue.

Interpreting data of the final EFLM-survey could lead to the conclusion that the overall quality of sampling time is very acceptable, because almost 87% participants for inpatients and 85% for outpatients reported that they can provide traceability of sampling time with good documentation at least for some samples. These results may seriously be questioned considering the following aspects.

The country-specific evaluation for Austrian participants of the final European survey only shows slightly lower results (69% for inpatients and 66% for outpatients, respectively) compared to the above-mentioned overall results from European responders. However, results from the Austrian pilot study, distributed among the same collective with a comparable number of participants (85 pilot study/65 final study), revealed a far lower number of 29% of responders who stated sufficient sampling time quality for all or most samples. This difference reflects the weakness of surveys in general as these findings suggest biased results due to a kind of expectancy bias or peer pressure leading participants to respond in a way they think is appropriate, or due to misinterpreting the question.

This impression is reconfirmed by EFLM WG-PRE experts, which report a low number of exact sampling time documentation in their health care setting (answers in Tables 1 and 2 “excellent quality” for “inpatients/other staff” 6% and “outpatients” 25%). Additionally, unlike the finding of the final EFLM questionnaire, the survey among the experts shows a substantial better quality of sampling time information for outpatients compared to inpatients. Potential reasons include the fact that blood from outpatients is usually drawn shortly after the request for laboratory tests is made, or that blood collection for outpatients is performed by laboratory staff in many facilities. Unlike this situation, laboratory requests for inpatients are usually placed in advance, stating an assumed time of blood collection, which does not always correspond to the exact time of drawing blood. Moreover, blood collection is mostly carried out by non-laboratory staff in clinical wards, who sometimes tend to have lower education and training on good phlebotomy practice, thus lacking the knowledge of poor sample time documentation on analytical quality. This rational is also supported by the difference in documentation quality between phlebotomist and “other staff” sampling in the inpatient setting (Answer “excellent” in Tables 1 and 2 “inpatients/phlebotomists” 33% versus “inpatients/other staff” 6%). Another aspect for a higher documentation quality in outpatients is that technical devices, such as mobile handhelds, or stationary hardwired apparatus are expensive and are not available in all phlebotomy settings. The survey among national WG-PRE representatives shows a few outpatients sampling sites equipped with these technical devices.

Another interesting finding was the fact that 45%–64% of laboratories which stated to be accredited according to the ISO 15189 regulation do not have information on all sampling time data, although this guideline demands it [1] (Figure 1).

Considering the high clinical importance of knowing the exact sampling time in order to correctly interpret the stability of specific analytes, addressing correct reference ranges for analytes with a high circadian rhythm or to calculate the correct total turnaround time (TAT), it is disappointing that very little emphasis has been put on this issue in the past. Despite overwhelming evidence on the impact of durations from blood collection to sample analysis in current literature [12], [13], [14], [15], scarce information can be found on if and how sampling time is assessed.

As a limitation of this study, we want to mention that the WG-PRE experts have only described the situation in their local laboratories and specific healthcare environment, so that the scenario may not be ideally representative of their entire country. Therefore, our finding only represent an approximation of the situation at the time of the survey.

Possible solutions

Recognizing the actual situation in most European laboratories as improvable concerning the documentation of sampling time, it is important to discuss which solutions for documentation are already available and can be implemented.

A structured overview of existing and future solutions should motivate laboratory representatives to focus on improving this important issue. As current evidence on this neglected issue is scarce, possible advantages and disadvantages are reported from the authors’ point of view. A structured overview is presented in Table 4.

Table 4:

Possible solutions for documenting correct sampling times.

Requirements Advantages Limitation/disadvantages
Paper-based request Appropriate paper forms carriers (staff available to carry papers) Easily available

Easy to use

Independent from electricity, power supply, IT system downtime
Low compliance in entering correct sampling times

Illegibility/transcription errors

Manual entry of sampling time with respective source of uncertainty

Need of regular paper forms supply
Computerized physician order entry system (CPOE) HIS-, LIS-interface Easily available

Electronic documentation of sampling time
Low compliance in entering correct sampling times

Manual entry of sampling time with respective source of uncertainty
Handheld ID device Continuous WiFi access Automated documentation of sampling time Cost intensive

(one time investment)
Automatic tube labeling system LIS-interface Automated documentation of sampling time Cost intensive

(one time investment)
Pre-labeled barcodes-tubes LIS-interface dedicated devices continuous WiFi access Automated documentation of sampling time

Simplification and standardization of phlebotomy process
Extra costs

(continuous investment) Changes in laboratory organization

No written patient information on the tubes (only barcode)
Smart rack based technology LIS-interface Automated documentation of sampling time Cost intensive

(one time investment)
Extended point of care blood sugar devices LIS-connected POC-devices Automated documentation of sampling time

Devices already in use

Low to medium costsa
Modified POC-LIS interface/currently not available
Phlebotomist Human resources Easy to train correct sampling

Adapt to special situations
Cost intensive

(continuous investment)

  1. POC, point of care; LIS, laboratory information system; HIS, hospital information system; aDepending on the local setting and availability and distribution of respective POC devices including network connections.

Paper-based request

Probably the easiest, but least valuable, means of tracking blood collection times entails paper-based requesting, where the collecting staff member has to provide clear, written information. From personal experiences of the authors, respective compliance in filling out respective fields for the time of sampling is low. Therefore, this method will most likely lead to poor sample time quality at best. Additionally, this method bares potential errors of illegibility and transcription.

Computerized physician order entry (CPOE) system

A similar solution is the use of an LIS with functionality of computerized physician order entry (CPOE) extension or interface to an external CPOE. This system, although electronic, has the same drawbacks as the paper based version, namely the low compliance of users to consequently enter correct sampling times. Even if this entry is made mandatory, orders are often registered long before blood is collected, especially for inpatients, making respective timestamps unreliable.

The usually available options in clinical settings all over Europe are these first two (paper based request forms and CPOE). Both systems provide a heterogeneous quality for sampling time. If just a few people do work with the system, for example, in an outpatient clinic, it is possible to achieve satisfactory documentation quality. Nevertheless, the quality obviously drops in settings where more people are involved. The advantages of these solutions are the low costs and the availability on every computer. From our survey, we can see that these systems are widespread all over Europe.

Single (extra) handheld device

For documentation of sampling time and other clinically important information related to the sampling process, some health care settings have implemented dedicated devices [16], [17], or based on smartphones or tablets, equipped with specific, usually in-house developed software (app) for the purpose of simplifying the administrative part of blood collections including timepoint documentations.

The fact that these devices are only dedicated to phlebotomy procedures without any conflict with other clinical processes bears many potential advantages such as respective software focusing solely on issues like identification of sample collector, minimization of patient misidentification, phlebotomist guidance throughout sample collection process and so forth. Although some of these solutions are already commercially available in some countries, the additional costs for hardware and software are often exceeding local budgets.

Automatic tube labeling system

Another solution, especially for outpatient wards, encompasses the use of automated tube labeling systems [18]. These devices are designed to improve automation in test requests, patient identification, tube and container specimen selection, labeling and check out, with a complete traceability of the process, including time stamping. Hence, such instruments may aid in phlebotomist guidance throughout the sample collection process, recognition of blood tubes by cap color, optimizing label position on tube, minimizing preanalytical errors such as patient misidentification and others. Most importantly, time stamps are collected and documented into the hospital information system (HIS/LIS) via a two-way online interface, one of the requirements of this system, apart from a continuous power supply. When other blood collection tubes come into use or the tube lot changes, an instrument re-calibration for color recognition might be necessary. As implantation of such instruments on all wards of a hospital would be financially unsustainable, they are mostly used in outpatient wards or phlebotomy centers with high patient throughput.

Pre-labeled barcodes-tubes

Apart from blood sampling tubes with blank or no label, so-called “pre-barcoded” tubes are available from some vendors [19]. The barcode incorporates a unique alphanumeric code, especially produced for specific customers. Orders are only registered in the order entry system, without printing labels. During the sampling process, the patient (wristband) and the pre-barcoded collection tubes are scanned, so that the blood collection time is automatically tracked. Subsequently, the combination of patient and sample information is transferred to the LIS for further processing. As LISs usually produce the sample barcode in their own system, this process is combined with bigger change in LIS or comprehensive new interfaces. An implementation of this system requires dedicated devices for barcode scanning and, if used as non-stationary, continuous WiFi access for data transfer. The missing patient data on the tube may have advantages in terms of data security and disadvantages in terms of archiving. It surely helps in improving patient misidentification errors and simplifying phlebotomy processes, as no additional barcode printer is necessary. Similar to the above-mentioned solutions, extra costs for dedicated devices as well as the slightly higher costs for these special tubes compared to those without label have to be considered. In clinical settings where these system are implemented, mainly positive effects on some preanalytical quality indicators were reported [20]. However, overriding the automatically set sampling time or manual entry shall be enabled in certain circumstances (e.g. loss of network connection, device malfunction, etc.).

Smart rack-based technology

In many clinical settings a complete supply with network connectivity including WiFi Access is not available. In these situations, a technology supporting all sampling information to be transported accompanying the sample to the laboratory is an advantage. The so-called “smart rack” technology fulfills these requirements [21]. Directly after sampling, all collected tubes as well as the patient and the phlebotomist are identified by scanning respective barcodes (e.g. patient wristband). Gathered information is stored on the radio frequency identification (RFID) tacks of the rack and the tubes are put in a given position in the rack. When samples are registered in the laboratory, the rack information is automatically transferred to the LIS. For this last step, an interface between the smart rack server and the LIS is necessary. At the sampling site a power supply for scanning and RFID writing devices is required. Comparable to other solutions, minimization of preanalytical errors, like patient misidentification, is also achievable with this technique. Additional monitoring of transport temperature between two laboratories may be achieved by using especially equipped transport boxes. Preanalytically affected tubes, for example, due to prolonged transport time or wrong transport temperature or even missing tubes can be easily identified at sample reception. Monitoring and statistic evaluation of preanalytical parameter can be done based on the acquired information. Costs for the system itself, the smart racks, all sampling devices and potential temperature-monitoring-boxes need to be considered before implementation of this solution.

Point-of-care (POC) blood sugar devices

Most of the afore-mentioned solutions require some sort of financial investment. The results of the survey presented in this article highlight that economic issues are one of the main reasons for the lack of better solutions so far. In many European clinical environments, POC test (POCT) glucose measuring devices are already implemented including a local area network (LAN) or wireless-LAN (WLAN) connection to the local network. An interface to the LIS for transferring patient test results is also often available. These existing connections could be used for implementing a new functionality for these devices. Adaption of software and slightly modified interface between POC device and LIS would be necessary to extend the actual functionality, transforming it into a scanning device for routine blood collections. The functionality in the sampling process could be comparable to the afore-mentioned single handheld devices, but without extra costs. Additional costs could, however, emerge if additional network connections or devices are needed, depending on the local setting.

Ongoing discussions with vendors of these devices spark the hope that the necessary software extensions could be available soon. Depending on the software change and the existing communication between device and LIS (unidirectional or bidirectional), further support of the sampling process could hence be predictable. For future tenders of POC glucometers, extension of a corresponding functionality could be considered.

Phlebotomist

In the USA, phlebotomist as specialists in blood collection are widely established (http://www.phlebotomy.org/). In Europe, this profession is still rarely seen (e.g. in the UK) in most countries, as a survey carried out by the WG-PRE throughout 28 European countries shows [22]. This finding could be confirmed by our survey among preanalytical experts. These results also show that collection time is better documented when blood is collected by phlebotomists. In order to establish this allocation of blood sampling, human resources, ideally assigned to the laboratory and only dedicated to the task of phlebotomy, are required. Once established, this new unit needs specialized training and re-training to sustain sampling quality. Comparable to other processes, the quality in the blood collection process may improve by involving fewer and better educated employees. Such initiatives may also generate better communication between professions and lead to better understanding of nurses and clinicians on the impact of preanalytical errors on laboratory test results. High cost, addressed as additional personnel, is an often-heard limitation of phlebotomist’s implementation. However, these resources may be acquired by simply re-distributing phlebotomy tasks from nurses or other personnel. Additionally, when considering all secondary costs that may be reduced by implementation of phlebotomists (e.g. reduction in repeated blood sampling), such interventions may even be cost-neutral.

Conclusions

The sampling time is a necessary and valuable information in laboratory medicine. As many formal processes such as accreditation do actually request this task, many laboratories throughout Europe are challenged in providing high quality documentation. Even if this a universal requirement in laboratory medicine, the actual situation all over Europe shows a lack of acceptable documentation quality. There are already some solutions available, which provide higher quality than paper-based or electronic CPOE-based solutions. These innovative strategies have not reached widespread popularity so far, mainly due to their relevant costs. High quality solutions, such as assessment with already implemented devices like POCT-glucometers, could help improving the current situation, but are also not available everywhere so far.

Acknowledgments

We want to thank Dr. Christoph Buchta for aiding in the distribution of the Austrian pilot survey.

  1. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  2. Research funding: None declared.

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.

  5. Competing interests: Authors state no conflict of interest.

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Received: 2020-03-07
Accepted: 2020-04-27
Published Online: 2020-06-05
Published in Print: 2020-09-25

©2020 Walter de Gruyter GmbH, Berlin/Boston