The relationship between vacuum and hemolysis during catheter blood collection: a retrospective analysis of six large cohorts

Background:

Blood collection through intravenous (IV) catheters is a common practice at emergency departments (EDs). This technique is associated with higher in vitro hemolysis rates and may even be amplified by the use of vacuum collection tubes. Our aim was to investigate the association of five different vacuum tubes with hemolysis rates in comparison to an aspiration system under real-life conditions and to propose an equation to estimate the amount of hemolysis, depending on the vacuum collection tube type.

Methods:

We retrospectively evaluated hemolysis data of plasma samples from our ED, where blood is drawn through IV catheters. Over the past 5 years, we compared 19,001 hemolysis index values amongst each other and against the respective vacuum pressure (Pv) of the collection tubes, which were used within the six observational periods.

Results:

The highest hemolysis rates were associated with full-draw evacuated tubes. Significantly reduced hemolysis was observed for two kinds of partial-draw tubes. The hemolysis rate of one partial-draw blood collection tube was comparable to those of the aspiration system. Regression analysis of Pv and mean free hemoglobin (fHb) values yielded the formula fHb (g/L)=0.0082*Pv2–0.1143*Pv+ 0.5314 with an R2 of 0.99.

Conclusions:

If IV catheters are used for blood collection, hemolysis rates directly correlate with the vacuum within the tubes and can be estimated by the proposed formula. By the use of partial-draw vacuum blood collection tubes, hemolysis rates in IV catheter collections can be reduced to levels comparable with collections performed by aspiration systems.

Various glycolysis inhibitor-containing tubes for glucose measurement cannot be used interchangeably due to clinically unacceptable biases between them

Background:

The aim of our study was to determine the difference between glucose concentration measured 30 min after venipuncture in ice-chilled heparin plasma sample and all currently available citrate buffer-containing tubes (Greiner Glucomedics, Greiner FC Mix and Sarstedt GlucoEXACT) and still widely used sodium fluoride/potassium oxalate (NaF/Kox) tubes from Greiner.

Methods:

Blood was collected from 20 healthy volunteers and 20 patients with diabetes into LiH, NaF/KOx, Glucomedics, FC mix and GlucoEXACT tubes. Glucose was measured within 30 min from blood sampling in duplicate on the Architect c8000 analyzer. Mean biases between all tube types were calculated and compared to the recommended criteria (1.95%). Additionally, glucose concentrations measured in all five tube types were compared using the Friedman test.

Results:

In the entire studied population, glucose concentrations measured in Glucomedics, FC mix and GlucoEXACT were higher (7.3%, 3.2% and 2.0%, respectively) than in the ice-chilled LiH tubes. When all glycolysis inhibitor-containing tubes were compared, Glucomedics tubes significantly differed from GlucoEXACT and FC mix tubes (biases −4.9% and 4.0%, respectively). In addition, there was a significant difference between the NaF/KOx tube and Glucomedics, as well as FC mix tubes (biases 7.1% and 3.0%, respectively).

Conclusions:

Glucose concentrations measured in recommended ice-chilled lithium heparin- and citrate buffer-containing tubes are not comparable. Significant biases exist between various glycolysis inhibitor-containing tubes; therefore, they cannot be used interchangeably.

The EFLM strategy for harmonization of the preanalytical phase

The Working Group for the Preanalytical Phase (WG-PRE) was officially established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) in 2013, with the aim of improving harmonization in the preanalytical phase across European member societies. Since its early birth, the WG-PRE has already completed a number of projects, including harmonizing the definition of fasting status, patient and blood tubes identification, color coding of blood collection tubes, sequence of tubes during blood drawing and participation in the development of suitable preanalytical quality indicators. The WG-PRE has also provided guidance on local validation of blood collection tubes, has performed two European surveys on blood sampling procedures and has organized four European meetings to promote the importance of quality in the preanalytical phase. The future activities entail development and validation of an external quality assessment scheme focused on preanalytical variables, development and dissemination of a survey about the local management of unsuitable samples in clinical laboratories, as well as release of EFLM phlebotomy guidelines. This article summarizes all recent achievements of the WG-PRE and illustrates future projects to promote harmonization in the preanalytical phase.

Hemolysis rates in blood samples: differences between blood collected by clinicians and nurses and the effect of phlebotomy training

BACKGROUND

Hemolytic samples are one of the most challenging preanalytical issues in laboratory medicine. Even causes leading to hemolytic specimen are various, including phlebotomy practices. Respective educational interventions as well as the reduction of the number of people involved in blood collections are claimed to influence the sample quality for the better. In our hospital 70 junior doctors were in charge of routine phlebotomy until 2012, when this task was shifted to 874 nurses, including a preceding training in phlebotomy and preanalytics. Our aim was to evaluate the impact of this training effect and the increase of people involved on sample quality.

METHODS

The hemolysis index (HI) of 43,875 samples was measured before (n=21,512) and after (n=22,363) the switch of blood collection responsibilities. Differences in overall hemolysis rates and the amount of plasma samples with a concentration of free hemoglobin (fHb) above 0.5 g/L and 1 g/L were calculated.

RESULTS

Overall HI as well as the percentage of samples with an fHb concentration >0.5 g/L decreased after the responsibility for phlebotomy changed. The rate of samples with an fHb concentration >1 g/L remained unchanged.

CONCLUSIONS

Hemolysis rates were reduced upon passing phlebotomy tasks from untrained physicians on to a trained nursing staff. We therefore conclude that the number of people performing phlebotomy seems to play a minor role, compared to the effect of a standardized training. However, whether a reduction in the number of people involved in blood collection could lead to further improvement of sample quality, remains to be investigated in future studies.

Patient identification and tube labelling - a call for harmonisation

Venous blood sampling (phlebotomy) is the most common invasive procedure performed in patient care. Guidelines on the correct practice of phlebotomy are available, including the H3-A6 guideline issued by the Clinical Laboratory Standards Institute (CLSI). As the quality of practices and procedures related to venous blood sample collection in European countries was unknown, the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for the Preanalytical Phase conducted an observational study in 12 European countries. The study demonstrated that the level of compliance of phlebotomy procedures with the CLSI H3-A6 guideline was unacceptably low, and that patient identification and tube labelling are amongst the most critical steps in need of immediate attention and improvement. The process of patient identification and tube labelling is an essential safety barrier to prevent patient identity mix-up. Therefore, the EFLM Working Group aims to encourage and support worldwide harmonisation of patient identification and tube labelling procedures in order to reduce the risk of preanalytical errors and improve patient safety. With this Position paper we wish to raise awareness and provide recommendations for proper patient and sample identification procedures.

Preanalytical external quality assessment of the Croatian Society of Medical Biochemistry and Laboratory Medicine and CROQALM: finding undetected weak spots

INTRODUCTION

The aim of this paper is to present results of first two years of preanalytical external quality assessment (EQA) in Croatia.

MATERIALS AND METHODS

This paper summarizes results from 6 rounds of preanalytical EQA during 2014-2016 in 161-175 Croatian laboratories (number ranged between cycles). EQA was designed as an online survey of the compliance with National recommendations for phlebotomy (NRP). Forty-seven questions in 5 categories are analyzed (materials and equipment, patient identification, patient preparation, sampling and storage). Additionally, preanalytical cases are presented. Overall performance scores (Question score (Qscore) for compliance with NRP and Case score (Cscore) for preanalytical cases) are calculated for each question/case as a proportion of laboratories with satisfactory procedure (x 100). Qscores and Cscores ≥ 70 were classified as acceptable (maximal score = 100).

RESULTS

In investigation of compliance with NRP, acceptable Qscores were obtained for 34/47 questions. The lowest scores were observed for the availability of sterile disposable tourniquets (Qscore = 15) and safe-sharp needles (Qscore = 34), obtaining patients address as an identifier (Qscore = 21), using glycolysis inhibitor tubes for glucose concentration measurement (Qscore = 21) and verification of manufacturers declarations on temperature and time of storage (Qscore = 31). There was no statistically significant difference in overall Qscore according to different categories of phlebotomy procedures (P = 0.284). The results of preanalytical cases showed acceptable Cscore values for all cases (89-96).

CONCLUSION

First two years of preanalytical EQA showed good compliance with the NRP and excellent expertise in resolving complex preanalytical issues. Major critical spots are lack of availability of safe-sharp needles, disposable tourniquets and glucose inhibitor tubes.

EFLM WG-Preanalytical phase opinion paper: local validation of blood collection tubes in clinical laboratories

The selection or procurement of blood collection devices in healthcare facilities is often an underestimated issue. This is probably due to different factors including the lack of knowledge of policymakers, hospital administrators and even laboratory managers about the importance of preanalytical quality and phlebotomy process, as well as to the absence of reliable guidelines or recommendations on how to precisely assess the quality of blood collection devices around the globe. With the awareness that a gap remains between manufacturers' and local validation of blood collection devices, the Working Group for Preanalytical Phase (WG-PRE) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has drafted a consensus document aimed to provide a set of essential requisites, technical criteria (e.g. presence of physical defects, malfunctioning, safety problems) and clinical issues for supporting laboratory professionals in organization blood collection tubes tenders and validating new devices before local routine implementation. The laboratory professionals should also make sure that the tenders accurately and strictly define the responsibilities for validation experiments and the potential consequences in the case the validation outcome shows that tubes due not fulfill the expectations.

Is peritoneal dialysis causing a measurable burden of inflammatory and endothelial injury on top of metabolic syndrome?

PURPOSE

Low-grade chronic inflammation is present in patients on peritoneal dialysis (PD) and in metabolic syndrome (MS). Due to possible greater endothelial changes in dialyzed patients, inflammatory response and oxidative stress are probably stronger in patients on PD. The objective of the study was to investigate possible in between adipokines, inflammatory, endothelial and oxidative stress markers between MS patients and patients on PD.

METHODS

Concentrations of adipokines (leptin, resistin), inflammatory markers [interleukin-6 (IL-6), soluble tumor necrosis factor alpha receptor (sTNF-R), myeloperoxidase (MPO), monocyte chemoattractant protein 1 (MCP-1)] and endothelial markers [soluble intracellular adhesion molecule-1 (sICAM-1), soluble CD40 ligand (sCD40L)] were determined in 55 MS patients and 18 patients on PD, with flow cytometry, and visfatin concentration was measured with ELISA. Routine biochemistry parameters were measured on Beckman Coulter AU2700 analyzer.

RESULTS

Patients on PD have significantly higher concentration of: CRP [6.5 (3.7-12.1) versus 2.6 (1.3-4.0) mg/L, P < 0.001], IL-6 [13.83 (8.48-31.31) versus 2.05 (0.67-4.11) pg/mL, P < 0.001], MCP-1 [2172.28 (1563.84-2922.77) versus 1353.58 (1166.33-1961.70) pg/mL, P = 0.023], sTNF-R [18.25 (12.81-25.22) versus 1.23 (0.89-1.43) ng/mL, P < 0.001] and sICAM-1 [830.03 (599.21-967.02) versus 463.85 (315.25-751.71) ng/mL, P = 0.006] than subjects with MS. MS patients have higher concentrations of MPO [175.47 (120.15-231.67) versus 101.76 (53.55-186.06) ng/mL, P = 0.016] and visfatin [1.5 (0.9-2.3) versus 0.9 (0.6-1.6) ng/mL, P = 0.013].

CONCLUSION

In patients on PD, inflammatory reaction is higher than in patients with MS. On the contrary, patients with MS have stronger oxidative stress response and adipose tissue activity caused probably by the chronic low level of inflammation and underlying metabolic disorders.

Order of blood draw: Opinion Paper by the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for the Preanalytical Phase (WG-PRE)

It has been well reported over recent years that most errors within the total testing process occur in the pre-analytical phase (46%–68.2%), an area that is usually outside of the direct control of the laboratory and which includes sample collection (phlebotomy). National and international (WHO, CLSI) guidelines recommend that the order of draw of blood during phlebotomy should be blood culture/sterile tubes, then plain tubes/gel tubes, then tubes containing additives. This prevents contamination of sample tubes with additives from previous tubes that could cause erroneous results. There have been a number of studies recently looking at whether order of draw remains a problem with modern phlebotomy techniques and materials, or it is an outdated practice followed simply because of historical reasons. In the following article, the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for the Preanalytical Phase (EFLM WG-PRE) provides an overview and summary of the literature with regards to order of draw in venous blood collection. Given the evidence presented in this article, the EFLM WG-PRE herein concludes that a significant frequency of sample contamination does occur if order of draw is not followed during blood collection and when performing venipuncture under less than ideal circumstances, thus putting patient safety at risk. Moreover, given that order of draw is not difficult to follow and knowing that ideal phlebotomy conditions and protocols are not always followed or possible, EFLM WG-PRE supports the continued recommendation of ensuring a correct order of draw for venous blood collection.

Improving quality in the preanalytical phase through innovation, on behalf of the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for Preanalytical Phase (WG-PRE)

It is now undeniable that laboratory testing is vital for the diagnosis, prognostication and therapeutic monitoring of human disease. Despite the many advances made for achieving a high degree of quality and safety in the analytical part of diagnostic testing, many hurdles in the total testing process remain, especially in the preanalytical phase ranging from test ordering to obtaining and managing the biological specimens. The Working Group for the Preanalytical Phase (WG-PRE) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has planned many activities aimed at mitigating the vulnerability of the preanalytical phase, including the organization of three European meetings in the past 7 years. Hence, this collective article follows the previous three opinion papers that were published by the EFLM WGPRE on the same topic, and brings together the summaries of the presentations that will be given at the 4th EFLM-BD meeting “Improving quality in the preanalytical phase through innovation” in Amsterdam, 24–25 March, 2017.

Standardizing in vitro diagnostics tasks in clinical trials: a call for action

Translational research is defined as the process of applying ideas, insights and discoveries generated through basic scientific inquiry to treatment or prevention of human diseases. Although precise information is lacking, several lines of evidence attest that up to 95% early-phase studies may not translate into tangible outcomes for improving clinical management. Major theoretical hurdles exist in the translational process, but is it also undeniable that many studies may have failed for practical reasons, such as the use of inappropriate diagnostic testing for evaluating efficacy, effectiveness or safety of a given medical intervention, or poor quality in laboratory testing. This can generate biased test results and result in misconceptions during data interpretation, eventually leading to no clinical benefit, possible harm, and a waste of valuable resources. From a genuine economic perspective, it can be estimated that over 10 million euros of funding may be lost each year in clinical trials in the European Union due to preanalytical and analytical problems. These are mostly attributions to the heterogeneity of current guidelines and recommendations for the testing process, to the poor evidence base for basic pre-analytical, analytical and post-analytical requirements in clinical trials, and to the failure to thoughtfully integrate the perspectives of clinicians, patients, nurses and diagnostic companies in laboratory best practices. The most rational means for filling the gap between what we know and what we practice in clinical trials cannot discount the development of multidisciplinary teams including research scientists, clinicians, nurses, patients associations and representative of in vitro diagnostic (IVD) companies, who should actively interplay and collaborate with laboratory professionals to adapt and disseminate evidence-based recommendations about biospecimen collection and management into the research settings, from preclinical to phase III studies.

Compliance of blood sampling procedures with the CLSI H3-A6 guidelines: An observational study by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) working group for the preanalytical phase (WG-PRE)

BACKGROUND

An observational study was conducted in 12 European countries by the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for the Preanalytical Phase (EFLM WG-PRE) to assess the level of compliance with the CLSI H3-A6 guidelines.

METHODS

A structured checklist including 29 items was created to assess the compliance of European phlebotomy procedures with the CLSI H3-A6 guideline. A risk occurrence chart of individual phlebotomy steps was created from the observed error frequency and severity of harm of each guideline key issue. The severity of errors occurring during phlebotomy was graded using the risk occurrence chart.

RESULTS

Twelve European countries participated with a median of 33 (18-36) audits per country, and a total of 336 audits. The median error rate for the total phlebotomy procedure was 26.9 % (10.6-43.8), indicating a low overall compliance with the recommended CLSI guideline. Patient identification and test tube labelling were identified as the key guideline issues with the highest combination of probability and potential risk of harm. Administrative staff did not adhere to patient identification procedures during phlebotomy, whereas physicians did not adhere to test tube labelling policy.

CONCLUSIONS

The level of compliance of phlebotomy procedures with the CLSI H3-A6 guidelines in 12 European countries was found to be unacceptably low. The most critical steps in need of immediate attention in the investigated countries are patient identification and tube labelling.

The role of European Federation of Clinical Chemistry and Laboratory Medicine Working Group for Preanalytical Phase in standardization and harmonization of the preanalytical phase in Europe

Patient safety is a leading challenge in healthcare and from the laboratory perspective it is now well established that preanalytical errors are the major contributor to the overall rate of diagnostic and therapeutic errors. To address this, the European Federation of Clinical Chemistry and Laboratory Medicine Working Group for Preanalytical Phase (EFLM WG-PRE) was established to lead in standardization and harmonization of preanalytical policies and practices at a European level. One of the key activities of the WG-PRE is the organization of the biennial EFLM-BD conference on the preanalytical phase to provide a forum for National Societies (NS) to discuss their issues. Since 2012, a year after the first Preanalytical phase conference, there has been a rapid growth in the number of NS with a working group engaged in preanalytical phase activities and there are now at least 19 countries that have one. As a result of discussions with NS at the third conference held in March 2015 five key areas were identified as requiring harmonisation. These were test ordering, sample transport and storage, patient preparation, sampling procedures and management of unsuitable specimens. The article below summarises the work that has and will be done in these areas. The goal of this initiative is to ensure the EFLM WG-PRE produces work that meets the needs of the European laboratory medicine community. Progress made in the identified areas will be updated at the next preanalytical phase conference and show that we have produced guidance that has enhanced standardisation in the preanalytical phase and improved patient safety throughout Europe.

Colour coding for blood collection tube closures - a call for harmonisation

At least one in 10 patients experience adverse events while receiving hospital care. Many of the errors are related to laboratory diagnostics. Efforts to reduce laboratory errors over recent decades have primarily focused on the measurement process while pre- and post-analytical errors including errors in sampling, reporting and decision-making have received much less attention. Proper sampling and additives to the samples are essential. Tubes and additives are identified not only in writing on the tubes but also by the colour of the tube closures. Unfortunately these colours have not been standardised, running the risk of error when tubes from one manufacturer are replaced by the tubes from another manufacturer that use different colour coding. EFLM therefore supports the worldwide harmonisation of the colour coding for blood collection tube closures and labels in order to reduce the risk of pre-analytical errors and improve the patient safety.

Preanalytical quality improvement. In pursuit of harmony, on behalf of European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working group for Preanalytical Phase (WG-PRE)

Laboratory diagnostics develop through different phases that span from test ordering (pre-preanalytical phase), collection of diagnostic specimens (preanalytical phase), sample analysis (analytical phase), results reporting (postanalytical phase) and interpretation (post-postanalytical phase). Although laboratory medicine seems less vulnerable than other clinical and diagnostic areas, the chance of errors is not negligible and may adversely impact on quality of testing and patient safety. This article, which continues a biennial tradition of collective papers on preanalytical quality improvement, is aimed to provide further contributions for pursuing quality and harmony in the preanalytical phase, and is a synopsis of lectures of the third European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)-Becton Dickinson (BD) European Conference on Preanalytical Phase meeting entitled 'Preanalytical quality improvement. In pursuit of harmony' (Porto, 20-21 March 2015). The leading topics that will be discussed include unnecessary laboratory testing, management of test request, implementation of the European Union (EU) Directive on needlestick injury prevention, harmonization of fasting requirements for blood sampling, influence of physical activity and medical contrast media on in vitro diagnostic testing, recent evidence about the possible lack of necessity of the order of draw, the best practice for monitoring conditions of time and temperature during sample transportation, along with description of problems emerging from inappropriate sample centrifugation. In the final part, the article includes recent updates about preanalytical quality indicators, the feasibility of an External Quality Assessment Scheme (EQAS) for the preanalytical phase, the results of the 2nd EFLM WG-PRE survey, as well as specific notions about the evidence-based quality management of the preanalytical phase.

Glucose is stable during prolonged storage in un-centrifuged Greiner tubes with liquid citrate buffer, but not in serum and NaF/KOx tubes

Delayed sample processing can affect accurate glucose measurement. Our aim was to investigate the stability of glucose in samples collected in serum, sodium fluoride/potassium oxalate (NaF/KOx) and Glucomedics tubes processed according to different controlled pre-centrifugation delays (up to 180 min after venipuncture) in order to simulate prolonged sample transport between venipuncture and centrifugation.

Samples were collected from healthy volunteers (n=80) into either serum or NaF/KOx and Glucomedics tubes. Glucose concentration was measured in samples centrifuged immediately after venipuncture and compared with tubes processed with a delay of 60, 120 and 180 min prior to centrifugation. Differences between baseline and respective delayed centrifugation glucose value for each tube type were tested using the paired t-test. Mean bias calculated for each tube type and delay protocol was compared to recommended quality specifications for glucose (2.2%).

Glucose concentrations measured in all three delayed tube types were lower in comparison to respective baseline glucose concentrations measured in immediately processed tube (p<0.001). The highest decrease in glucose was observed in serum tubes in all specified time points (p<0.001), while glucose was most stable in Glucomedics tubes (p<0.001). The decrease in glucose observed for serum and NaF/KOx tubes was clinically significant at all specified time points while the bias for Glucomedics tubes did not exceed the criteria even with a centrifugation delay of 180 min.

Glucose stability in un-centrifuged Glucomedics tubes is much superior to serum and NaF/KOx tubes. Glucomedics tubes can be left un-centrifuged for up to 3 h without affecting glucose concentration.

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples

Endogenous interferences are an important source of biased laboratory results. Hemolysis, lipemia and icteria are the main source of endogenous interference in laboratory medicine. Accreditation according to ISO 15189 improves the overall quality of the laboratory procedures. The aim of our study was i) to assess the level of knowledge of Croatian medical biochemists about the proper detection and management of hemolysis, lipemia and icteria; and ii) to identify possible differences in the level of knowledge respective to the laboratory accreditation status.

An on-line self-report survey was carried out by the Working Group for Preanalytical Phase of the Croatian Society of Medical Biochemistry and Laboratory Medicine during April to May 2015. Survey included 14 statements (Q1–Q14) about procedures for samples with interferences and participants were asked to assess the degree of agreement with the statement using a 4-point Likert scale.

The lowest level of knowledge was observed for statements Q10 (dealing with icteric sample; 40.9% participants agreed with the correct procedure), Q12 (allowable error for interference; 47.2%) and Q11 (dealing with lipemic sample; 60.1%). Almost all participants (97.4%) agreed that laboratories in Croatia should have a harmonized protocol for management of samples with interferences. Participants from accredited laboratories showed higher knowledge of hemolysis detection (p=0.031), rejection of hemolyzed sample (p<0.001), management of icteric samples (p=0.038) and allowable error for interferences (p=0.040).

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples. Accreditation is associated with higher knowledge about management of samples with interferences.