Prevalence and type of pre-analytical problems for inpatients samples in coagulation laboratory

Effect of hemolysis on D-dimer testing measured with the Improgen kit: is all manufacturer information correct?

D-dimer is a fibrin degradation product and its measurement is affected by hemolysis. This study was designed to reveal the value of hemolysis affecting D-dimer in our laboratory. In this study, hemolysate samples obtained by both mechanical and freezing methods were used. D-dimer levels of all plasmas were measured with Improgen Diagnostic kit by immune-turbidimetric method. Numerical change in hemolyzed samples was evaluated by calculating the percentage difference, and clinically significant differences were evaluated by calculating the maximum acceptable bias (MAB). In the hemolysate study prepared by both freeze-thaw and mechanical methods, it was observed that low D-dimer levels did not exceed the total allowable error (TAE) (30%) up to +2 hemolysis (corresponds to hemoglobin = 1.01-2 g/l) and did not exceed the MAB (65%) even at +4 hemolysis (corresponds to hemoglobin = 1.01-2 g/l). High D-dimer levels did not exceed the limit values of both TAE (30%) and MAB (68%) even in +4 hemolysis. The D-dimer test was affected by lower levels of hemolysis compared to both other studies and the values in the kit insert (hemoglobin >5 g/l corresponds to +4 hemolysis index). We verified the hemolysis interference in the D-dimer test, which we thought was not compatible with the kit insert, under our own laboratory conditions. This is the first hemolysis interference study performed with the Improgen brand d-dimer kit. In samples with a hemolysis rate of +2 and above, it would be more accurate to reject the D-dimer result as a 'hemolyzed sample'.

[How to interpret and pursue a prolonged quick time or APTT]

The standard hemostasis workup [quick time (QT), and activated partial thrombin time (APTT)] is very commonly prescribed but its interpretation is often difficult for practitioners who are not specialized in hemostasis. Here, we review the principles of the diagnostic approach to these tests. Only a very basic knowledge of the coagulation cascade is necessary to identify which clotting factor tests to prescribe and to interpret the results. Deficiency in several clotting factors suggests liver dysfunction, disseminated intravascular coagulation (DIC) or vitamin K deficiency. If a single factor is deficient, we review the different causes of acquired deficiencies and briefly discuss the characteristics of the different congenital defects, which generally require specialized management. Lupus anticoagulant is a common and generally benign cause of prolonged APTT to be aware of, which is not related to a hemorrhagic risk. A good knowledge of the diagnostic approach to abnormal QT or APTT generally allows the resolution of the most common situations.

Analysis of the Six Sigma Principle in Pre-analytical Quality for Hematological Specimens

Introduction Blood tests are essential for detecting and treating hospitalized individuals with diseases. Laboratory blood tests provide doctors with critical information required to treat their patient's illnesses. The most common sources of error in clinical laboratories are pre-analytical errors. Although quality control measures can remediate analytical errors, there is a requirement for stringent quality checks in the pre-analytical sector as these activities are performed outside of the laboratory. Pre-analytical errors when combined with the sigma value can reflect a better picture as the sigma value represents the laboratory's performance.  Aim In this study, six sigma and the Pareto principle were utilized to assess pre-analytical quality indicators for evaluating the performance of a clinical hematology laboratory.  Methodology  This is a retrospective observational study conducted from 2015 to 2023 (for a period of eight years). Information about the frequency of pre-analytical errors was retrieved from the hematology section of the central diagnostic research laboratory information system and the data was entered into an MS Excel sheet and data was evaluated utilizing SPSS version 23 (IBM Corp., Armonk, NY). Results In the current research, total of 15 pre-analytical errors were noted. Out of the total 15 pre-analytical errors studied, 55.4% of pre-analytical errors were noted among which 80% errors were due to lack of mention of sample type or received time and 20% of errors were attributed to no mention of diagnosis in requisition forms. The next most common errors noted were insufficient samples (8.26%) followed by absence of physician's signature (7%), incomplete request form (5.4%), age (4.2%), unique hospital identification (UHID) number (3.7%), clotted samples and transportation of the samples (3.6%), date and incorrect vials (2.6%). Gender (0.95%), hemolysed (0.85%), and lipemic samples (0.45%). Hemolysed and lipemic samples had a sigma value of 4.4 and 4.6, respectively, whereas gender and age had a sigma value of 4.3 and 3.8, inadequate sample for testing and an incorrect anticoagulant to blood ratio had a sigma value of 3.6, indicating that sample collection has to be improved as the inverse relationship is noted between sigma value and laboratory performance. Conclusion Pareto chart and sigma value can help recognize most common pre-analytical errors, which consequently will help to prevent further recurrence of pre-analytical errors. Adequate training with regard to best practices in phlebotomy for interns, clinicians and technicians must be provided to decrease quantitative errors, which will further enhance total quality management in the laboratory.

D-dimer Testing in Pulmonary Embolism with a Focus on Potential Pitfalls: A Narrative Review

D-dimer is a multifaceted biomarker of concomitant activation of coagulation and fibrinolysis, which is routinely used for ruling out pulmonary embolism (PE) and/or deep vein thrombosis (DVT) combined with a clinical pretest probability assessment. The intended use of the tests depends largely on the assay used, and local guidance should be applied. D-dimer testing may suffer from diagnostic errors occurring throughout the pre-analytical, analytical, and post-analytical phases of the testing process. This review aims to provide an overview of D-dimer testing and its value in diagnosing PE and discusses the variables that may impact the quality of its laboratory assessment.

Detecting Preanalytical Errors Using Quality Indicators in a Hematology Laboratory

BACKGROUND AND OBJECTIVES

Monitoring laboratory performance continuously is crucial for recognizing errors and fostering further improvements in laboratory medicine. This study aimed to review the quality indicators (QIs) and describe the laboratory errors in the preanalytical phase of hematology testing in a clinical laboratory.

METHODS

All samples received in the Hematology Laboratory of the Maternity and Pediatric Hospital in Hail for 3 years were retrospectively reviewed and evaluated for preanalytical issues using a set of QIs. The rate of each QI was compared to the quality specifications cited in the literature.

RESULTS

A total of 95002 blood samples were collected for analysis in the hematology laboratory from January 2017 through December 2019. Overall, 8852 (9.3%) were considered to show preanalytical errors. The most common were "clotted specimen" (3.6%) and "samples not received" (3.5%). Based on the quality specifications, the preanalytical QIs were classified generally as low and medium level of performance. In contrast, the sigma-based performance level indicates acceptable performance on all the key processes. Further analysis of the study showed a decreasing rate of preanalytical errors from 11.6% to 6.5%.

CONCLUSIONS

Preanalytical errors remain a challenge to hematology laboratories. The errors in this case were predominantly related to specimen collection procedures that compromised the specimen quality. Quality indicators are a valuable instrument in the preanalytical phase that allows an opportunity to improve and explore clinical laboratory process performance and progress. Continual monitoring and management of QI data are critical to ensure ongoing satisfactory performance and to enhance the quality in the preanalytical phase.

The impact of laboratory staff training workshops on coagulation specimen rejection rates

Background

Pre-analytical variables can have a significant adverse impact on the quality and credibility of coagulation test results. Therefore, correct and consistent identification of pre-analytical variables that compromise coagulation specimen quality is of paramount importance. Lack of standardization and heterogeneity among laboratory staff when assessing coagulation specimens can lead to inconsistent identification of these variables. Failure to recognize such pre-analytical variables results in the analysis of poor quality specimens and the authorization of spurious test results.

Objectives

To determine the impact of a laboratory staff training workshop on coagulation specimen rejection rates and to ascertain the level of knowledge of laboratory personnel concerning coagulation specimen rejection criteria before and after the workshop.

Methods

A retrospective three-month audit was performed with rejection data of incorrect blood to additive ratio, clotted, aged and haemolysed specimens collected. Training workshops and evaluation sessions were subsequently presented. A revised standard operating procedure delineating coagulation specimen rejection criteria was implemented and a repeat three-month audit was conducted.

Results

In total, 13 162 coagulation specimens were received during the initial audit with 1 104 specimens (8.39%) rejected. Following the workshops, the rejection rate increased by 3.49% to 11.88% with 12 743 coagulation specimens received and 1 514 specimens rejected. Evaluation sessions performed before and after the workshops revealed that 95.2% of attendees attained improved knowledge.

Conclusion

This study demonstrated the pivotal importance of regular laboratory staff training. The increase in specimen rejection following the workshops signifies their success in educating laboratory personnel regarding the correct identification of pre-analytical variables. Since most pre-analytical variables occur outside the laboratory, educational workshops need to be extended to non-laboratory personnel responsible for specimen collection and transport.

Analytical performance of a new immunoturbidimetric D‐dimer assay and comparison with available assays

Background

The routine D‐dimer quantification to exclude venous thromboembolism has led to the development of many assays, the usefulness of which depends on their reliability and performance.

Objective

We evaluated the analytical performances of the immunoturbidimetric Yumizen G DDi 2 assay (HORIBA Medical, Montpellier, France) performed on the Yumizen G800 analyzer and compared it with other available D‐dimer assays.

Methods

Within‐run and between‐run imprecision were evaluated using low‐ and high‐level quality‐control plasma samples. Interference due to hemolysis, icterus, lipemia, rheumatoid factor (RF), or heterophilic antibodies (human antimouse antibodies [HAMAs]) was evaluated by spiking plasma samples with hemolysate, bilirubin, Intralipid, RF, or HAMAs. The measurements obtained with the different D‐dimer assays were compared using Passing‐Bablok regression analysis and Bland‐Altman plot method, using fresh citrated plasma samples collected from 66 consecutive routine patients with a wide range of D‐dimer concentrations.

Results

Within‐ and between‐run variation coefficients for the Yumizen G DDi 2 assay ranged from 1.7% to 5.8% and from 2.8% to 5.5%, respectively. Hemolysis and icterus did not have any effect up to 10 g/L hemoglobin and 300 mg/L bilirubin. Lipemia seemed to generate an underestimation of D‐dimer concentration when the Intralipid concentration was >5 g/L. RF and HAMAs did not have any effect. The Passing‐Bablok and Bland‐Altman analyses showed small differences with other available D‐dimer assays, which were more pronounced with increasing values.

Conclusions

Its analytical performances and main technical features indicate that the new Yumizen G DDi 2 assay is suitable for the rapid quantification of D‐dimer in clinical hemostasis laboratories.

Capillary blood sampling increases the risk of preanalytical errors in pediatric hospital care: Observational clinical study

PURPOSE

The blood sampling procedure is complex and prone to failure, as reflected by preanalytical errors in pediatric hospital care. The primary aim was to evaluate if the risk of preanalytical errors was higher with capillary blood sampling than with venous blood sampling, and secondary, explore specific factors associated with preanalytical errors, both overall and stratified by capillary and venous blood sampling.

DESIGN AND METHODS

This observational pediatric hospital study collected outcomes from medical records and blood sampling surveys from year 2014 to 2016. The risk of preanalytical errors was analyzed with adjusted-odds ratio (adj-OR) by multivariable logistic regression with 95% confidence intervals (CIs).

RESULTS

Overall, 128 (13%) preanalytical errors were identified among 951 blood samples. The proportion and adj-OR of errors was significantly higher in capillary compared with venous blood samples, 72 (20%) of 354 versus 56 (9.4%) of 597, p = .001, adj-OR 2.88 (CI 1.79-4.64). Blood collection with multiple sample tubes was significantly associated with increased risk of preanalytical errors (n = 97 of 601, 16%), while log weight (kg) significantly decreased the risk of preanalytical errors adj-OR 0.66 (CI 0.50-0.86), indicating a protective effect of increasing weight. However, stratified analyses indicated a protective effect of increasing log weight for venous blood sampling adj-OR 0.52 (CI 0.38-0.72), but not capillary blood sampling, adj-OR 1.08 (CI 0.76-1.55).

CONCLUSION

This study indicates that capillary blood sampling collection increases the risk of preanalytical errors. Further, a child's increasing body weight reduced the risk of preanalytical errors, while multiple sample tube collections significantly increased the risk of preanalytical errors.

PRACTICE IMPLICATIONS

This new information may help nurses improve their knowledge concerning blood sampling collection in pediatrics. Altogether, this study also indicates that implementing more venous blood sampling and improve the cases of capillary sampling could reduce the number of preanalytical errors in pediatric hospitals.

International Council for Standardization in Haematology (ICSH) recommendations for processing of blood samples for coagulation testing

This guidance document has been prepared on behalf of the International Council for Standardization in Haematology (ICSH). The aim of the document is to provide guidance and recommendations for the processing of citrated blood samples for coagulation tests in clinical laboratories in all regions of the world. The following areas are included in this document: Sample transport including use of pneumatic tubes systems; clots in citrated samples; centrifugation; primary tube storage and stability; interfering substances including haemolysis, icterus and lipaemia; secondary aliquots-transport, storage and processing; preanalytical variables for platelet function testing. The following areas are excluded from this document, but are included in an associated ICSH document addressing collection of samples for coagulation tests in clinical laboratories; ordering tests; sample collection tube and anticoagulant; preparation of the patient; sample collection device; venous stasis before sample collection; order of draw when different sample types are collected; sample labelling; blood-to-anticoagulant ratio (tube filling); influence of haematocrit. The recommendations are based on published data in peer-reviewed literature and expert opinion.

International Council for Standardisation in Haematology (ICSH) recommendations for collection of blood samples for coagulation testing

This guidance document has been prepared on behalf of the International Council for Standardisation in Haematology (ICSH). The aim of the document is to provide guidance and recommendations for collection of blood samples for coagulation tests in clinical laboratories throughout the world. The following processes will be covered: ordering tests, sample collection tube and anticoagulant, patient preparation, sample collection device, venous stasis before sample collection, order of draw when different sample types need to be collected, sample labelling, blood-to-anticoagulant ratio (tube filling) and influence of haematocrit. The following areas are excluded from this document, but are included in an associated ICSH document addressing processing of samples for coagulation tests in clinical laboratories: sample transport and primary tube sample stability; centrifugation; interfering substances including haemolysis, icterus and lipaemia; secondary aliquots-transport and storage; and preanalytical variables for platelet function testing. The recommendations are based on published data in peer-reviewed literature and expert opinion.

Independent and combined effects of biotin and hemolysis on high-sensitivity cardiac troponin assays

OBJECTIVES

This study compared the independent and combined effects of hemolysis and biotin on cardiac troponin measurements across nine high-sensitivity cardiac troponin (hs-cTn) assays.

METHODS

Parallel cTn measurements were made in pooled lithium heparin plasma spiked with hemolysate and/or biotin using nine hs-cTn assays: Abbott Alinity, Abbott ARCHITECT i2000, Beckman Access 2, Ortho VITROS XT 7600, Siemens Atellica, Siemens Centaur, Siemens Dimension EXL cTnI, and two Roche Cobas e 411 Elecsys Troponin T-hs cTnT assays (outside US versions, with and without increased biotin tolerance). Absolute and percent cTn recovery relative to two baseline concentrations were determined in spiked samples and compared to manufacturer's claims.

RESULTS

All assays except the Ortho VITROS XT 7600 showed hemolysis and biotin interference thresholds equivalent to or greater than manufacturer's claims. While imprecision confounded analysis of Ortho VITROS XT 7600 data, evidence of biotin interference was lacking. Increasing biotin concentration led to decreasing cTn recovery in three assays, specifically both Roche Cobas e 411 Elecsys Troponin T-hs assays and the Siemens Dimension EXL. While one of the Roche assays was the most susceptible to biotin among the nine studied, a new version showed reduced biotin interference by approximately 100-fold compared to its predecessor. Increasing hemolysis also generally led to decreasing cTn recovery for susceptible assays, specifically the Beckman Access 2, Ortho VITROS XT 7600, and both Roche Cobas e 411 Elecsys assays. Equivalent biotin and hemolysis interference thresholds were observed at the two cTn concentrations considered for all but two assays (Beckman Access 2 and Ortho VITROS XT 7600). When biotin and hemolysis were present in combination, biotin interference thresholds decreased with increasing hemolysis for two susceptible assays (Roche Cobas e 411 Elecsys and Siemens Dimension EXL).

CONCLUSIONS

Both Roche Cobas e 411 Elecsys as well as Ortho VITROS XT assays were susceptible to interference from in vitro hemolysis at levels routinely encountered in clinical laboratory samples (0-3 g/L free hemoglobin), leading to falsely low cTn recovery up to 3 ng/L or 13%. While most assays are not susceptible to biotin at levels expected with over-the-counter supplementation, severely reduced cTn recovery is possible at biotin levels of 10-2000 ng/mL (41-8,180 nmol/L) for some assays. Due to potential additive effects, analytical interferences should not be considered in isolation.

Revisiting the effects of spectral interfering substances in optical end-point coagulation assays

INTRODUCTION

Hemolysis, icterus, and lipemia (HIL) are common pre-analytical variables in the clinical laboratory. Understanding their effects on coagulation laboratory results is essential.

METHODS

HIL effects on the prothrombin time (PT), activated partial thromboplastin time (APTT), dilute Russell's viper venom time (DRVVT), thrombin time (TT), and protein C chromogenic activity (CFx) were evaluated on the ACL TOP 750 optical analyzer and STA-R Evolution mechanical analyzer (PT and APTT only) by spiking normal donor, patient, and commercial control samples with varying concentrations of hemolysate, bilirubin, or a lipid emulsion. The relative difference or bias compared to the original results was determined.

RESULTS

Hemolysis (H) indices up to 900 mg/dL did not affect the APTT, PT, DRVVT Confirm, TT, and CFx; however, H indices above approximately 200 mg/dL resulted in a false-negative DRVVT screen and screen/confirm ratio in samples with a lupus anticoagulant. There was an artifactual prolongation of the PT and APTT when conjugated bilirubin was dissolved in aqueous solvents and not when it was dissolved in dimethyl sulfoxide. Icterus (I) indices up to 45 mg/dL did not result in significant (>15%) bias for all assays evaluated. The PT and APTT assays failed to produce a robust clot curve when the lipemia (L) index exceeded 6000 milliabsorbance units (mAbs), and the TT and DRVVT assays failed when the L index exceeded 3000 mAbs; the CFx assay was unaffected by lipemia.

CONCLUSIONS

Verification of the manufacturer's recommended interference thresholds is important since it may avoid inappropriate instrument flagging and/ or sample rejection.

The Cost of Pre-Analytical Errors in INR Testing at a Tertiary-Care Hospital Laboratory: Potential for Significant Cost Savings

BACKGROUND

Preanalytical errors account for most laboratory errors. Although the frequencies of preanalytical errors are well characterized in the literature, little is known regarding the costs of these errors to the laboratory.

OBJECTIVE

To analyze costs associated with preanalytical errors associated with the international normalized ratio (INR) test.

METHODS

We performed a retrospective analysis of INR requests associated with preanalytical error codes from January 2009 through September 2013. Preanalytical error types were those related to order entry (no specimen collected) and those unrelated to order entry (insufficient specimen quantity or specimen-integrity concerns). We calculated the cost of analysis of a specimen and the cost of investigating errors.

RESULTS

During the study period, there were 557,411 INR requests, 13.1% of which were associated with a preanalytical error code. The total annual cost of INR testing was USD $379,222.50. Investigation and reporting of preanalytical errors not related to order entry represented 10.5% of our annual INR testing budget (USD $39,939.00).

CONCLUSIONS

Minimizing preanalytical errors has the potential to result in significant cost savings.

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

D-dimer is a soluble fibrin degradation product deriving from the plasmin-mediated degradation of cross-linked fibrin. D-dimer can hence be considered a biomarker of activation of coagulation and fibrinolysis, and it is routinely used for ruling out venous thromboembolism (VTE). D-dimer is increasingly used to assess the risk of VTE recurrence and to help define the optimal duration of anticoagulation treatment in patients with VTE, for diagnosing disseminated intravascular coagulation, and for screening medical patients at increased risk of VTE. This review is aimed at (1) revising the definition of D-dimer; (2) discussing preanalytical variables affecting the measurement of D-dimer; (3) reviewing and comparing assay performance and some postanalytical variables (e.g. different units and age-adjusted cutoffs); and (4) discussing the use of D-dimer measurement across different clinical settings.

Retrospective study showed that blood sampling errors risked children's well-being and safety in a Swedish paediatric tertiary care

AIM

Blood analyses containing preanalytical errors (PAEs) are hazardous for patients. This study investigated the frequency of PAEs in blood analysis and the corresponding quality indicators of the sampling process in Swedish paediatric tertiary care.

METHODS

Data were retrieved from the laboratory at Astrid Lindgren Children's Hospital between 2013 and 2014. Preanalytical blood sampling performance was analysed according to the Six Sigma scale, ranging from 0 to 6 (933 137-3.4 defects per million [DPM]).

RESULTS

Of the 1 148 716 analyses, 61 656 (5.4%) were rejected due to PAEs. The PAEs ranged between hospital specialities from 1.9 to 9.4% (p < 0.001) and work shift times, from 6.0% in the day to 5.7% in the evening and 4.3% at night (p values <0.001). Clotting was the most prominent error (51.3%), affecting mostly haematology and coagulation analyses. Incorrectly filled samples represented almost 25% of all PAEs, with effects on chemistry, haematology and coagulation analyses. The sigma score for the overall preanalytical phase (3.2) corresponded to 44 565 DPM.

CONCLUSION

Samples with PAEs were frequently clotted and insufficiently filled, and the distribution of errors varied within working shifts and specific analyses. The overall quality control in paediatric blood sampling was barely acceptable.

The intra-assay reproducibility of thromboelastography in very low birth weight infants

BACKGROUND AND AIMS

Despite the potential benefits of thromboelastography (TEG) for bedside hemostatic assessment in critical care settings, its accuracy remains to be determined, especially in critically ill neonates. We determined the intra-assay reproducibility of TEG parameters: Reaction time (R), clot kinetics (K) and Maximum Amplitude (MA) in a cohort of very low birth weight (VLBW) infants.

STUDY DESIGN

Observational study.

SUBJECTS

One hundred VLBW newborns.

OUTCOME MEASURES

We performed TEG duplicate measurements for blood samples from VLBW newborns. To assess for correlation, we calculated the coefficients of correlation by plotting the values of the first vs the second measurement. Paired samples were compared with t-test and the coefficient of variation (CV) on paired results was also calculated as a measure of variability. To evaluate the agreement between duplicates, Bland-Altman (BA) analysis was performed.

RESULTS

We evaluated 228 TEG pairs. Both the coefficient of correlation and the BA analysis showed an acceptable level of agreement between duplicates. TEG variability (CV, mean ± SD) was highest for K (10.4%, ±12.9), lowest for MA (3.6%, ±8.0) and moderate for R (7.9%, ±9.0). The results from ANOVA one-way analysis describe different variability trends: K-CV increased at higher values, while MA-CV and R-CV increased at lower values.

CONCLUSIONS

In VLBW newborns, the agreement between TEG duplicate measurements for R and MA parameters is adequate for clinical purposes. TEG is a promising tool to quickly assess hemostasis ensuring a significant blood sparing in critically ill neonates.

Errors in the Hematology Laboratory at St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia

Objective

The objective of this study was to determine the magnitude of pre-analytical, analytical and post-analytical laboratory errors in hematology tests.

Results

A total of 2606 hematology requests were studied. Out of the total, 562 (21.6%) pre-analytic, 14 (0.5%) analytical and 168 (6.4%) post-analytical errors were recorded which contribute a total frequency of 75.5, 1.9 and 22.6%, respectively. The name of the physician requesting the test was not provided on 2215 (85%) of request forms and 1827 (70.1%) of the request forms were unaccompanied with proper clinical details of the patient. Essential information required on the request forms was often missed. Close communication between clinicians and laboratory personnel is the key to improve laboratory quality in general.

Relationship between various maternal conditions and lactic acid dehydrogenase activity in umbilical cord blood at birth

BACKGROUND

Lactic acid dehydrogenase (LDH) is a valuable marker for some of the most important diseases in newborns and the plasma LDH activity in newborns correlates well with conditions such as asphyxia. If LDH should be considered as a useful tool also in obstetric care, key factors associated with maternal health before and during pregnancy which could affect umbilical cord LDH activity need to be known. The aims of this study were to explore relationships between selected maternal conditions and arterial lactic acid dehydrogenase activity (aLDH) in umbilical cord blood at delivery.

METHODS

A prospective observational study was conducted at Sodersjukhuset, Stockholm, Sweden. Included in the study were 1247 deliveries, and cord blood samples from each were analyzed for aLDH. Background, delivery and neonatal data were collected from the medical records.

RESULTS

Higher median values of aLDH were found (P=0.001) among women with chronic disorders not related to pregnancy but there was no increased frequency of high aLDH levels (>612 μ/L, P=0.30). No difference in aLDH was identified between infants born to women with pregnancy-related disorders compared with healthy women, neither in median values, nor in high values (>612 μ/L, P=0.95).

CONCLUSION

Newborn infants born to women with non-pregnancy-related chronic disorders had a somewhat higher median value of aLDH in cord blood at delivery. The influence of common maternal conditions and diseases on umbilical cord arterial LDH levels is small compared to the increase reported in fetal distress and several other critical conditions in the newborn.

Making sense of a haemolysis monitoring and reporting system: a nationwide longitudinal multimethod study of 68 Australian laboratory participant organisations

Background:

The key incident monitoring and management systems (KIMMS) quality assurance program monitors incidents in the pre- and postanalytical phases of testing in medical laboratories. Haemolysed specimens have been found to be the most frequent preanalytical error and have major implications for patient care. The aims of this study were to assess the suitability of KIMMS for quality reporting of haemolysis and to devise a meaningful method for reporting and monitoring haemolysis.

Methods:

A structured survey of 68 Australian KIMMS laboratory participant organisations was undertaken. Quarterly haemolysis reports (2011–2014) were analysed.

Results:

Among 110 million accessions reported, haemolysis rates varied according to the reporting methods that participants used for assigning accessions (16% of participants reported haemolysis by specimen and 83% reported by episode) and counting haemolysis rejections (61% by specimen, 35% by episode and 3% by test). More than half of the participants (56%) assigned accessions by episode and counted rejections by specimen. For this group, the average haemolysis rate per 100,000 episodes was 177 rejected specimens with the average rate varying from 100 to 233 over time. The majority of participants (91%) determined rejections using the haemolysis index. Two thirds of participants (66%) recorded the haemolysis manually in laboratory information systems.

Conclusions:

KIMMS maintains the largest longitudinal haemolysis database in the world. However, as a means of advancing improvements in the quality of the preanalytical laboratory process, there is a need to standardise reporting methods to enable robust comparison of haemolysis rejection rates across participant laboratories.

Key factors influencing the incidence of hemolysis: A critical appraisal of current evidence

Hemolysis is a leading cause of pre-analytical laboratory errors. The identification of contributing factors is an important step towards the development of effective practices to reduce and prevent hemolysis. We performed a review of PUBMED, Embase, Medline and CINAHL to identify articles published between January 2000 and August 2016 that identified factors influencing in vitro hemolysis rates. The 40 studies included in this review provide excellent evidence that hemolysis rates are higher in Emergency Departments (EDs), for non-antecubital draws, for specimens drawn using an intravenous catheter compared to venipuncture and for samples transported by pneumatic tube compared to by hand. There is also good evidence that hemolysis rates are higher when specimens are not collected by professional phlebotomists, larger volume specimen tubes are used, specimen tubes are filled less than halfway and tourniquet time is greater than one minute. The results of this review suggest that hospitals and clinical laboratories should consider deploying phlebotomists in EDs, drawing all blood through a venipuncture, using the antecubital region as the optimum blood collection site and transporting specimens by laboratory assistant/other personnel, or if this in not practical, ensuring that pneumatic transport systems are validated, maintained and monitored. Studies also recommend making hemolysis a hospital-wide issue and ensuring high-quality staff training and adherence to standard operating procedures to reduce hemolysis rates. Awareness of the factors that influence hemolysis rates, and adoption of strategies to mitigate these risk factors, is an important step towards creating quality practices to reduce hemolysis rates and improve the quality of patient care.

Targeting Rejection: Analysis of Specimen Acceptability and Rejection, and Framework for Identifying Interventions in a Single Tertiary Healthcare Facility

OBJECTIVES

Assessment of specimen rejection rates is an important laboratory quality measure for laboratories because of a potential negative impact on patient care. Here, we examined reasons for specimen rejection at a single, tertiary care healthcare institution and propose a framework for designing an efficient intervention.

METHODS

During a 1-year period, we identified all specimens rejected at our hospital and performed an analysis of a wide range of associated variables: reason for rejection, patient location, type of phlebotomist, tests ordered, priority status, collection container used, transport time.

RESULTS

Clotted and hemolyzed specimens accounted for the majority of rejected specimens, but significant differences in reasons for specimen rejection existed between patient care areas. Eighty-five percent of rejected specimens came from the Emergency Department and eight other inpatient care areas. Registered nurses drew approximately 85% of rejected specimens, while laboratory phlebotomy staff drew only 4%.

CONCLUSIONS

While hemolysis and clotting are primary causes for specimen rejection, collection of all available data regarding specimen rejection data is essential for laboratories determining which factors are most significant causes of specimen rejection.

Test Cancellation: A College of American Pathologists Q-Probes Study

CONTEXT

Requests for laboratory testing are canceled after a specimen has already been collected from the patient for many reasons. Regardless of the cause, test cancellation represents a significant resource expenditure for laboratories, and many cancellation events impact patient care by delaying the reporting of test results.

OBJECTIVE

To survey a wide variety of hospitals to determine the rate, causes, and circumstances surrounding laboratory test cancellation events.

DESIGN

Institutions (N = 52) prospectively monitored their test cancellation events during a 6-week period or until 75 cancellation events occurred. Information regarding the test cancellation was recorded, including the primary reason for canceling the test. The rate of test cancellation was calculated based on laboratory specimen volume. Laboratory policies relevant to test cancellation were also surveyed.

RESULTS

A total of 3471 canceled tests were recorded by participating laboratories of 1,118,845 specimens they accessioned, resulting in an aggregate test cancellation rate of 3.1 per 1000 accessions. The most frequently reported reason for test cancellation occurred in the preanalytical phase, and was a duplicate test request, followed by specimen quality reasons including hemolyzed/clotted specimens and insufficient sample quantity for testing. Very few cancellations occurred during the analytical phase of testing. Lower test cancellation rates were reported by larger institutions and by laboratories that received fewer specimens from inpatients.

CONCLUSIONS

Cancellation of patient tests after a specimen had been collected and received remains a significant issue for clinical laboratories. Laboratories should monitor causes of test cancellation to identify targets for process improvement efforts and to improve laboratory utilization. Cancellation events due to incomplete identification or poor specimen quality potentially delay patient care. Cancellations due to duplicate orders or excessive frequency of testing represent operational challenges for the laboratory and inefficiency in the health care system. Policies related to test cancellation should be clearly specified and communicated to users of laboratory services.

Correction of Point-of-Care INR Results in Warfarin Patients

BACKGROUND

The measurement of international normalization ratio (INR) may be done by venous blood draw and use of a standard lab, or by fingerstick, using a point of care (POC) device such as the CoaguChek XS® (Roche Diagnostics), and the CoaguChek XS® has been validated to meet the International Organization for Standardization (ISO) performance requirements.

OVERVIEW

The goal of this study was to determine a correction factor for Coaguchek XS INR levels to a predicted venipuncture (VP) INR level.

METHODS

At the end of an anticoagulation clinic visit when a patient had an INR greater than or equal to 4, two INR results existed, that from the Coaguchek XS® meter and a venipuncture INR from the lab. The data were then discreetly recorded as a quality control for our clinic. The data were analyzed for possible significant trends between the two types of INR results.

RESULTS

The equation that was determined to be the best fit to the data was 0.621 × POC + 0.639 = estimated VP. The overall root mean square error (MSE) for the calculated correction was a 0.44 INR. The root mean square errors were 0.41 and 0.58 for the 4 to 5.9 and 6 to 7.9 POC INR groups, respectively.

CONCLUSION

The calculation that was derived in this study is not a surrogate for venipuncture INR in this clinic. However, the estimation of the INR may be useful clinically in guiding decision making in the future. (INR, Point of Care, Anticoagulation, Hematology).

The cost of poor blood specimen quality and errors in preanalytical processes

OBJECTIVES

The increase in the prevalence of medical errors represents a disturbing trend; hospital-based errors are the eighth leading cause of death in the United States. For the clinical laboratory, errors that occur in the preanalytical phase of testing may account for up to 75% of total laboratory errors; 26% of these may have detrimental effects on patient care, which contribute to unnecessary investigations or inappropriate treatment, increase in lengths of hospital stay, as well as dissatisfaction with healthcare services. This review focuses on these errors, particularly those observed in the preanalytical phase, and how they may affect clinical and financial outcomes. Financial ramifications are also demonstrated through a model that estimates the costs of preanalytical errors for the hospital and laboratory as well as patient care.

Impact of the phlebotomy training based on CLSI/NCCLS H03-a6 - procedures for the collection of diagnostic blood specimens by venipuncture

Introduction:

The activities involving phlebotomy, a critical task for obtaining diagnostic blood samples, are poorly studied as regards the major sources of errors and the procedures related to laboratory quality control. The aim of this study was to verify the compliance with CLSI documents of clinical laboratories from South America and to assess whether teaching phlebotomists to follow the exact procedure for blood collection by venipuncture from CLSI/NCCLS H03-A6 - Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture might improve the quality of the process.

Materials and methods:

A survey was sent by mail to 3674 laboratories from South America to verify the use of CLSI documents. Thirty skilled phlebotomists were trained with the CLSI H03-A6 document to perform venipuncture procedures for a period of 20 consecutive working days. The overall performances of the phlebotomists were further compared before and after the training program.

Results:

2622 from 2781 laboratories that did answer our survey used CLSI documents to standardize their procedures and process. The phlebotomists’ training for 20 days before our evaluation completely eliminated non-conformity procedures for: i) incorrect friction of the forearm, during the cleaning of the venipuncture site to ease vein location; ii) incorrect sequence of vacuum tubes collection; and iii) inadequate mixing of the blood in primary vacuum tubes containing anticoagulants or clot activators. Unfortunately the CLSI H03-A6 document does not caution against both unsuitable tourniquet application time (i.e., for more than one minute) and inappropriate request to clench the fist repeatedly. These inadequate procedures were observed for all phlebotomists.

Conclusion:

We showed that strict observance of the CLSI H03-A6 document can remarkably improve quality, although the various steps for collecting diagnostic blood specimens are not a gold standard, since they may still permit errors. Tourniquet application time and forearm clench should be verified by all quality laboratory managers in the services. Moreover, the procedure for collecting blood specimens should be revised to eliminate this source of laboratory variability and safeguard the quality.

Lipaemic donations: truth and consequences

The problem of using material of unsuitable quality, including "nontransparent turbid milky plasma" or more simply "turbid plasma", for producing blood components is not trivial for several epidemiological, technical, analytical, clinical and economical reasons. With some exception, most national and international guidelines mandate that blood components should preferably not be produced from lipaemic donations. The origin of lipaemic blood is variegated, and includes physiological or paraphysiological causes and metabolic disorders, whereas a broad range of common diseases and drugs can also be associated with hypertriglyceridaemia. Overall, the frequency of lipaemic donations ranges between 0.31% and 0.35%, although sporadic reports have highlighted that the frequency might be much higher, up to 13%. Lipaemic donations pose two leading problems in transfusion medicine, that are interference during laboratory testing, and safety of producing blood components from hypertriglyceridaemic materials. While the former issue can be overcome by using chemical or mechanical methods, the clinical use of lipaemic blood for producing components remains an unresolved question. Transfusion medicine should thereby embark on a landmark effort to find a universal agreement of behaviours and harmonization of policies worldwide.

Influence of mechanical trauma of blood and hemolysis on PFA-100 testing

Although the appropriate quality of samples is essential for platelet function testing, information is lacking on interference from mechanical trauma of blood and hemolysis on PFA-100 analyzer. Citrated blood collected from nine healthy volunteers was divided into three aliquots. The first aliquot ('A') was processed without further manipulation, whereas the second and third were subjected to mechanical trauma by two ('aliquot B') or four passages ('aliquot C') through a very fine needle (30 gauge) to produce hemolysis and cell trauma mimicking poor sample collection. Samples were tested on PFA-100 and Advia 2120, and plasma then separated and tested for lactate dehydrogenase (LDH) and hemolysis index. Negligible hemolysis was present in aliquot A (hemolysis index 0.2 ± 0.1, cell-free hemoglobin 0-0.5 g/l), whereas an increasing amount was present in aliquots B (hemolysis index of 13.1 ± 1.8, cell-free hemoglobin 6.0-6.5 g/l) and C (hemolysis index 24.0 ± 1.1, cell-free hemoglobin 11.5-12.0 g/l). Increases in LDH, and concomitant reductions in platelet and red blood cell counts were observed in aliquots B and C. In hemolyzed aliquots B, four out of nine samples yielded 'flow obstruction' with both PFA-100 agonist cartridges, whereas the closure times were dramatically prolonged in the remaining five samples. In hemolyzed aliquots C, flow obstruction was recorded in six of nine samples for collagen and ADP and all samples for collagen and epinephrine, whereas closure times of collagen and ADP in the remaining three samples were dramatically prolonged. Mechanical trauma of blood causing hemolysis makes PFA-100 testing unreliable. When flow obstructions are observed, the potential presence of hemolysis should be investigated.

Verifying reference intervals for coagulation tests by using stored data

OBJECTIVE

The purpose of the study was to verify the reference intervals for prothrombin time (PT) and activated partial thromboplastin time (APTT), using stored data of ambulatory pre-op subjects with exclusion of certain clinics, according to age and sex.

MATERIALS AND METHODS

Results of test requests (13,600 PT and 14,083 APTT) of subjects aged 15?80 made from outpatient clinics of surgical departments before surgical interventions in 2008 were retrieved from the electronic medical record. Thromborel S and Actin (Dade Behring, Germany) were used on the Sysmex® CA-1500 coagulation analyzer. Extreme values were determined by using Horn's algorithm after Box-Cox transformation, and the upper and lower reference limits were determined as the 2.5th and 97.5th percentiles of the cleaned data.

RESULTS

The values outside the interval of PT data 10.5-17.0 seconds and the interval of APTT data 20.6-35.8 seconds were excluded from the analysis. There were significant differences among age subsets of PT measurements ( p < 0.0001) and of APTT measurements ( p < 0.0001). Accordingly, the data were tested for gender differences and a significant difference was found in PT ( p = 0.002). APPT results did not differ statistically between men and women.

CONCLUSION

Although we found values different from the limits stated in the kit insert, it would be better to confirm our findings with the direct method, especially in APTT for patients under the age of 40 and over the age of 59, and also for sex differences in PT.

Influence of using a roller mixer on rejected samples in coagulation tests

INTRODUCTION

The influence of using a roller mixer just after blood collection on the ratio of rejected samples in coagulation tests was investigated retrospectively.

METHODS

Numbers of blood samples collected in centralized units of outpatient clinics for prothrombin time (PT) were 24,050 in group I and 24,500 in group II (H. Aral, unpublished data). In group I, the tubes were inverted manually. In group II, the tubes were left standing on roller mixer with 30 rpm. The ratios of rejected samples of the two groups were compared statistically with ki-square analysis.

RESULTS

Using a roller mixer, rate of rejection decreased from 0.79% (group I) to 0.20% (group II) (P<0.001).

CONCLUSION

We suggested using roller mixer to improve the reliability of coagulation testing. Such standardization in preanalytical phase may be helpful in preventing laboratory errors and obtaining correct test results in coagulation tests.

Blood sample collection and patient identification demand improvement: a questionnaire study of preanalytical practices in hospital wards and laboratories

Scand J Caring Sci; 2010; 24; 581-591 
 Blood sample collection and patient identification demand improvement: a questionnaire study of preanalytical practices in hospital wards and laboratories

BACKGROUND

  Most errors in venous blood testing result from human mistakes occurring before the sample reach the laboratory.

AIMS

  To survey venous blood sampling (VBS) practices in hospital wards and to compare practices with hospital laboratories.

METHODS

  Staff in two hospitals (all wards) and two hospital laboratories (314 respondents, response rate 94%), completed a questionnaire addressing issues relevant to the collection of venous blood samples for clinical chemistry testing.

RESULTS

  The findings suggest that instructions for patient identification and the collection of venous blood samples were not always followed. For example, 79% of the respondents reported the undesirable practice (UDP) of not always using wristbands for patient identification. Similarly, 87% of the respondents noted the UDP of removing venous stasis after the sampling is finished. Compared with the ward staff, a significantly higher proportion of the laboratory staff reported desirable practices regarding the collection of venous blood samples. Neither education nor the existence of established sampling routines was clearly associated with VBS practices among the ward staff.

CONCLUSIONS

  The results of this study, the first of its kind, suggest that a clinically important risk of error is associated with VBS in the surveyed wards. Most important is the risk of misidentification of patients. Quality improvement of blood sample collection is clearly needed, particularly in hospital wards.

The prevalence of preanalytical errors in a Croatian ISO 15189 accredited laboratory

BACKGROUND

The preanalytical phase is the most common source of laboratory errors. The goal of this descriptive study was to analyze the prevalence and type of preanalytical errors in relation to the site of sample collection (inpatient vs. outpatient) and the type of laboratory unit (hematology and coagulation vs. biochemistry). For the biochemistry unit, the data were also analyzed relative to the type of the analysis (stat vs. routine).

METHODS

We retrospectively analyzed the sample and test request form error rate for a 1-year period, from January to December 2008.

RESULTS

The frequency of the sample errors differed significantly between the emergency and routine biochemistry unit (0.69% vs. 2.14%; p<0.0001), and between inpatients and outpatients (1.12% vs. 1.36%; p=0.0006). Hemolysis was the most frequent sample error, accounting for 65% of all unsuitable specimens in the emergency biochemistry unit. The total sample error rate did not differ between hematology and coagulation vs. the biochemistry unit. The frequency of test request form errors differed significantly with respect to the sample collection site (p<0.0001), laboratory unit (p<0.0001) and type of the analysis (p<0.0001). Errors in the test request form were least frequent in the outpatient unit (2.98%) and most frequent in the routine biochemistry unit (65.94%).

CONCLUSIONS

Sample and test request form errors in our laboratory are occurring with a frequency comparable to that reported by others. Continuous educational action is needed for all stakeholders involved in laboratory testing to improve the quality of the preanalytical phase of the total testing process.

Is the test result correct? A questionnaire study of blood collection practices in primary health care

RATIONALE, AIMS AND OBJECTIVES

Venous blood tests are important for clinical decision making. Most errors in blood testing are due to human errors before the blood samples reach the laboratory. The present study was designed to investigate venous blood sampling (VBS) practices in primary health care centres (PHCs) compared with clinical laboratory staff.

METHOD

A cross-sectional survey of 70 PHCs and two clinical laboratories is conducted. All staff responsible for VBS (317 respondents, response rate 94%) completed a questionnaire on VBS practices.

RESULTS

Instructions for VBS were not followed in the surveyed PHCs. For example, only 54% reported that they always identified the patient by using name/Swedish identification number and only 5% reported that they always used photo-ID, the two preferred means for patient identification. Only 12% reported that they always released venous stasis as soon as possible. Fewer PHC staff than clinical laboratory staff reported correct VBS practices. For example, 54% of the PHC staff reported that they always identified the patient by name and Swedish identification number, as compared with 95% of the clinical laboratory staff (P < 0.001). Documented VBS routines and re-education in VBS were not clearly associated with reported correct VBS practices.

CONCLUSIONS

In the surveyed PHCs, there are clinically important risks for misidentification of patients and erroneous test results, with consequences for the diagnosis and treatment of patients. Quality interventions, aimed at improving VBS practices, are needed to ensure patient safety.

Governance of preanalytical variability: travelling the right path to the bright side of the moon?

Medical errors can be traditionally clustered into 4 categories, which include errors of diagnosis, errors of treatment, errors of prevention, and an 'other miscellaneous' category. Owing to the volume and complexity of testing, and considering that laboratory error is defined as any defect from ordering tests to reporting results and appropriately interpreting and reacting on these, it is not surprising that mistakes in the total testing process occur with frequency, have connections to all four types of medical errors and represent a serious hazard for patient health. Throughout the laboratory diagnostics, preanalytical problems prevail. Moreover, the positive trends towards reduction of laboratory errors over the past decade, particularly those in the analytical phase, has little involved the preanalytical phase, which actually represents the most critical area to target. In particular, the high frequency of errors still attributable to processes external to the laboratory requires additional efforts for the governance of this mistreated phase of the total testing process, so that we can finally find the right path to progress from the dark to the bright side of the moon. As for any other type of medical errors, the most effective path to improvement is the implementation of a total quality management system, encompassing a multifaceted strategy for process and risk analysis, based on error prevention, detection, and management.