Impact of optimizing pre-analytical phase on the diagnosis of gestational diabetes and related outcomes.

OBJECTIVES: Pre-analytical plasma glucose (PG) sampling methodology may significantly affect gestational diabetes mellitus (GDM) incidence, but no studies directly examined the impact on perinatal outcomes. We compared the effect on oral glucose tolerance test (OGTT) results of using for blood sampling the traditional sodium fluoride (NaF) tubes, batched at controlled temperature, and the more effective citrate-buffered tubes, in terms of GDM diagnosis and related outcomes. METHODS: We evaluated 578 pregnant women performing OGTT between 24- and 28-weeks' gestation. Paired NaF and citrate blood samples were drawn and analyzed for PG. GDM diagnosis was made by applying the 'one-step' American Diabetes Association strategy. Data on perinatal outcomes were collected in a subset of 330 women who delivered in our hospital network. RESULTS: Using the standard NaF approach, 69 (11.9%) GDM women were detected. Using citrate PG values, 90 women were additionally identified as GDM, increasing the GDM prevalence to 27.5%. Perinatal outcomes were analyzed according to the different diagnostic allocation (NaF-diagnosed GDM, additional citrate-diagnosed GDM, and no GDM). NaF-diagnosed GDM showed a higher incidence of large for gestational age (LGA) (p=0.034), and of cesarean and preterm delivery (p<0.01) vs. no GDM. The only outcome remaining more frequent in the additional citrate diagnosed GDM when compared with no GDM group was LGA (17.2 vs. 6.8%, p=0.025). CONCLUSIONS: If a health care system plans to use citrate tubes for GDM diagnosis, considerations about clinical implications are mandatory by balancing higher sensitivity in detecting a poor glycemic control with effects on outcomes to avoid "overdiagnosis".

Optimization of the Preanalytical Phase by Estimating Serum Indices Using an Automated Classifier.

BACKGROUND: Most laboratory errors occur in the preanalytical phase. Among the most common preanalytical errors are interferences due to hemolysis, lipemia, and icterus. Our objective was to evaluate a serum interference estimation methodology by the RSD classifier, to identify other biochemical parameters affected by preanalytical interferences, and to determine the economic impact of its implementation. METHODS: The serum indices of 65,529 requests measured by the RSD system and by the analytical determination on the Cobas 711 or Cobas 8000 platforms were collected. We proceeded to the search for association patterns between the serum indices and laboratory analytical tests using data mining techniques. The influence of the preanalytical interferences was evaluated in 91 laboratory tests that include biochemistry, immunoassay, and coagulation. The savings estimation after the implementation of this methodology was made by time series models. RESULTS: The evaluation of the generated model showed compatibilities between the methods used (94.4% accuracy). The implementation of a protocol for serum indices estimation by the RSD would avoid the unnecessary analysis of the tests which are affected by interferences, achieving an estimated annual savings of €10,561. In addition, it allowed the estimation of bilirubin values which would add an annual savings of €4,900 in our laboratory. On the other hand, data mining techniques have allowed us to identify the following laboratory tests affected by hemolysis which are not usually considered in laboratories: iron, transferrin, fibrinogen, and alkaline phosphatase. CONCLUSIONS: The RSD classifier is an efficient estimation method of serum indices and it allows the estimation of bilirubin values. The implementation of this methodology in our laboratory could lead to an estimated annual savings of more than €15,000 without increasing response times. Iron, alkaline phosphatase, transferrin, and fibrinogen should be included in the evaluated procedure.

Heparin and citrate additive carryover during blood collection.

Background Published evidence on the risk of additive carryover during phlebotomy remains elusive. We aimed to assess potential carryover of citrated and heparinized blood and the relative volume needed to bias clinical chemistry and coagulation tests. Methods We simulated standardized phlebotomies to quantify the risk of carryover of citrate and heparin additives in distilled water, using sodium and lithium as surrogates. We also investigated the effects of contamination of heparinized blood samples with increasing volumes of citrated blood and pure citrate on measurements of sodium, potassium, chloride, magnesium, total and ionized calcium and phosphate. Likewise, we studied the effects of contamination of citrated blood samples with increasing volumes of heparinized blood on heparin (anti-Xa) activity, lithium, activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT). We interpreted these results based on measurement deviations beyond analytical, biological and clinical significance. Results Standardized phlebotomy simulations revealed no significant differences in concentration of surrogate markers. Clinically significant alterations were observed after contamination of heparinized blood samples with volumes of citrated blood beyond 5-50 µL for ionized calcium and beyond 100-1000 µL for sodium, chloride and total calcium. Investigations of pure citrate carryover revealed similar results at somewhat lower volumes. Heparinized blood carryover showed clinically significant interference of coagulation testing at volumes beyond 5-100 µL. Conclusions Our results suggest that during a standardized phlebotomy, heparin or citrate contamination is highly unlikely. However, smaller volumes are sufficient to severely alter test results when deviating from phlebotomy guidelines.

Pre-analytical practices for routine coagulation tests in European laboratories. A collaborative study from the European Organisation for External Quality Assurance Providers in Laboratory Medicine (EQALM).

Background Correct handling and storage of blood samples for coagulation tests are important to assure correct diagnosis and monitoring. The aim of this study was to assess the pre-analytical practices for routine coagulation testing in European laboratories. Methods In 2013-2014, European laboratories were invited to fill in a questionnaire addressing pre-analytical requirements regarding tube fill volume, citrate concentration, sample stability, centrifugation and storage conditions for routine coagulation testing (activated partial thromboplastin time [APTT], prothrombin time in seconds [PT-sec] and as international normalised ratio [PT-INR] and fibrinogen). Results A total of 662 laboratories from 28 different countries responded. The recommended 3.2% (105-109 mmol/L) citrate tubes are used by 74% of the laboratories. Tube fill volumes ≥90% were required by 73%-76% of the laboratories, depending upon the coagulation test and tube size. The variation in centrifugation force and duration was large (median 2500 g [10- and 90-percentiles 1500 and 4000] and 10 min [5 and 15], respectively). Large variations were also seen in the accepted storage time for different tests and sample materials, for example, for citrated blood at room temperature the accepted storage time ranged from 0.5-72 h and 0.5-189 h for PT-INR and fibrinogen, respectively. If the storage time or the tube fill requirements are not fulfilled, 72% and 84% of the respondents, respectively, would reject the samples. Conclusions There was a large variation in pre-analytical practices for routine coagulation testing in European laboratories, especially for centrifugation conditions and storage time requirements.

Continual improvement of the pre-analytical process in a public health laboratory with quality indicators-based risk management.

Background Quality indicators (QIs) and risk management are important tools for a quality management system designed to reduce errors in a laboratory. This study aimed to show the effectiveness of QI-based risk management for the continual improvement of pre-analytical processes in the Kayseri Public Health Laboratory (KPHL) which serves family physicians and collects samples from peripheral sampling units. Methods QIs of pre-analytical process were used for risk assessment with the failure modes and effects analysis (FMEA) method. Percentages and risk priority numbers (RPNs) of QIs were quantified. QI percentages were compared to the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) performance specifications and RPNs were compared to risk level scale, and corrective actions planned if needed. The effectiveness of risk treatment actions was re-evaluated with the new percentages and with RPNs of predefined QIs. Results RPNs related to four QIs required corrective action according to the risk evaluation scale. After risk treatment, the continual improvement was achieved for performance and risk level of "transcription errors", for risk levels of "misidentified samples" and "not properly stored samples" and for the performance of "hemolyzed samples". "Not properly stored samples" had the highest risk score because of sample storage and centrifugation problems of peripheral sampling units which are not under the responsibility of the KPHL. Conclusions Public health laboratories may have different risk priorities for pre-analytical process. Risk management based on predefined QIs can decrease the risk levels and increase QI performance as evidence-based examples for continual improvement of the pre-analytical process.

Preanalytical robustness of blood collection tubes with RNA stabilizers.

Background Efficient blood stabilization is essential to obtaining reliable and comparable RNA analysis data in preclinical operations. PAXgene (Qiagen, Becton Dickinson) and Tempus (Applied Biosystems, Life Technologies) blood collection tubes with RNA stabilizers both avoid preanalytical degradation of mRNA by endogenous nucleases and modifications in specific mRNA concentrations by unintentional up- or down-regulation of gene expression. Methods Sixteen different preanalytical conditions were tested in PAXgene and Tempus blood samples from seven donors: different mixing after collection, different fill volumes and different 24-h transport temperature conditions after collection. RNA was extracted by column-based methods. The quality of the extracted RNA was assessed by spectrophotometric quantification, A260/A280 purity ratio, RNA Integrity Number (Agilent Bioanalyzer), miRNA quantative real time polymerase chain reaction (qRT-PCR) on two target miRNAs (RNU-24 and miR-16), mRNA quality index by qRT-PCR on the 3' and 5' region of the GAPDH gene, and the PBMC preanalytical score, based on the relative expression levels of the IL8 and EDEM3 coding genes. Results When PAXgene RNA and Tempus blood collection tubes were used following the manufacturers' instructions, there was no statistically or technically significant difference in the output RNA quality attributes. However, the integrity of the RNA extracted from Tempus collection tubes was more sensitive to fill volumes and effective inversion, than to storage temperature, while the integrity of RNA extracted from PAXgene collection tubes was more sensitive to effective inversion and storage temperature than to fill volumes. Conclusions Blood collection tubes with different RNA stabilizers present different robustness to common preanalytical variations.

Optimized procedures for testing plasma metanephrines in patients on hemodialysis.

Diagnosis of pheochromocytomas and paragangliomas in patients receiving hemodialysis is troublesome. The aim of the study was to establish optimal conditions for blood sampling for mass spectrometric measurements of normetanephrine, metanephrine and 3-methoxytyramine in patients on hemodialysis and specific reference intervals for plasma metanephrines under the most optimal sampling conditions. Blood was sampled before and near the end of dialysis, including different sampling sites in 170 patients on hemodialysis. Plasma normetanephrine concentrations were lower (P < 0.0001) and metanephrine concentrations higher (P < 0.0001) in shunt than in venous blood, with no differences for 3-methoxytyramine. Normetanephrine, metanephrine and 3-methoxytyramine concentrations in shunt and venous blood were lower (P < 0.0001) near the end than before hemodialysis. Upper cut-offs for normetanephrine were 34% lower when the blood was drawn from the shunt and near the end of hemodialysis compared to blood drawn before hemodialysis. This study establishes optimal sampling conditions using blood from the dialysis shunt near the end of hemodialysis with optimal reference intervals for plasma metanephrines for the diagnosis of pheochromocytomas/paragangliomas among patients on hemodialysis.

The pre-analytical phase of the liquid biopsy.

The term 'liquid biopsy', introduced in 2013 in reference to the analysis of circulating tumour cells (CTCs) in cancer patients, was extended to cell-free nucleic acids (cfNAs) circulating in blood and other body fluids. CTCs and cfNAs are now considered diagnostic and prognostic markers, used as surrogate materials for the molecular characterisation of solid tumours, in particular for research on tumour-specific or actionable somatic mutations. Molecular characterisation of cfNAs and CTCs (especially at the single cell level) is technically challenging, requiring highly sensitive and specific methods and/or multi-step processes. The analysis of the liquid biopsy relies on a plethora of methods whose standardisation cannot be accomplished without disclosing criticisms related to the pre-analytical phase. Thus, pre-analytical factors potentially influencing downstream cellular and molecular analyses must be considered in order to translate the liquid biopsy approach into clinical practice. The present review summarises the most recent reports in this field, discussing the main pre-analytical aspects related to CTCs, cfNAs and exosomes in blood samples for liquid biopsy analysis. A short discussion on non-blood liquid biopsy samples is also included.

Quality Control of Preanalytical Handling of Blood Samples for Future Research: A National Survey.

BACKGROUND: Assessment and control of preanalytical handling of blood samples for future research are essential to preserve integrity and assure quality of the specimens. However, investigation is limited on how quality control of preanalytical handling of blood samples is performed by biobanks. METHODS: A questionnaire was sent to all Danish departments of clinical biochemistry, all Danish departments of clinical immunology, the Danish Health Surveillance Institution and the Danish Cancer Society. The questionnaire consisted of questions regarding preanalytical handling of samples for future research. The survey was carried out from October 2018 until the end of January 2019. RESULTS: A total of 22 departments (78%) replied, of which 17 (77%) performed preanalytical quality control of the blood samples. This quality control consisted of patient preparation, temperature surveillance of freezers, maintenance of centrifuges, and visual inspection for hemolysis, lipemia, and sample volume. Automated sample check for hemolysis, icterus, and lipemia interferences was performed by 41% of respondents, not performed by 50% of respondents, and 9% did not answer. The majority (55%) of the participants stated that they had no local standard operating procedure for preanalytical handling of samples for research projects. CONCLUSIONS: The preanalytical phase for blood samples obtained and preserved for future research in Denmark is highly heterogeneous, although many aspects (e.g., hemolysis, which also affects DNA analyses, metabolomics, and proteomics) seems highly relevant to document. Our findings emphasize the need to optimize and standardize best practices for the preanalytical phase for blood samples intended for use in future research projects.

[Recommendations for urinary organic acids analysis]. / Recommandations concernant l'analyse des acides organiques urinaires.

Biochemical diagnosis of hereditary metabolic diseases requires the detection and simultaneous identification of a large number of compounds, hence the interest in metabolic profiles. Organic acid chromatography allows the identification of several hundred compounds and the quantification of the main molecules of interest. As part of the accreditation process for medical biology examinations according to standard NF EN ISO 15189, the group from the French society for inborn errors of metabolism (SFEIM) recommends an approach to accredit organic acid chromatography. Validation parameters and recommendations are discussed in this specific framework.

Strict Preanalytical Oral Glucose Tolerance Test Blood Sample Handling Is Essential for Diagnosing Gestational Diabetes Mellitus.

OBJECTIVE: Preanalytical processing of blood samples can affect plasma glucose measurement because ongoing glycolysis by cells prior to centrifugation can lower its concentration. In June 2017, ACT Pathology changed the processing of oral glucose tolerance test (OGTT) blood samples for pregnant women from a delayed to an early centrifugation protocol. The effect of this change on the rate of gestational diabetes mellitus (GDM) diagnosis was determined. RESEARCH DESIGN AND METHODS: All pregnant women in the Australian Capital Territory (ACT) are recommended for GDM testing with a 75-g OGTT using the World Health Organization diagnostic criteria. From January 2015 to May 2017, OGTT samples were collected into sodium fluoride (NaF) tubes and kept at room temperature until completion of the test (delayed centrifugation). From June 2017 to October 2018, OGTT samples in NaF tubes were centrifuged within 10 min (early centrifugation). RESULTS: A total of 7,509 women were tested with the delayed centrifugation protocol and 4,808 with the early centrifugation protocol. The mean glucose concentrations for the fasting, 1-h, and 2-h OGTT samples were, respectively, 0.24 mmol/L (5.4%), 0.34 mmol/L (4.9%), and 0.16 mmol/L (2.3%) higher using the early centrifugation protocol (P < 0.0001 for all), increasing the GDM diagnosis rate from 11.6% (n = 869/7,509) to 20.6% (n = 1,007/4,887). CONCLUSIONS: The findings of this study highlight the critical importance of the preanalytical processing protocol of OGTT blood samples used for diagnosing GDM. Delay in centrifuging of blood collected into NaF tubes will result in substantially lower rates of diagnosis than if blood is centrifuged early.

Improvement of Blood Samples Preanalytic Management Alters the Clinical Results of Glucose Values: Population Study.

BACKGROUND: Prolonged time elapsing between the blood drawing and separation of the cell mass may result in decreased sample glucose levels due to continuous glycolysis. This can lead to underdiagnoses of hyperglycemic states and overdiagnosis of hypoglycemia. We aimed to evaluate the clinical impact of shortened transit time and earlier centrifugation of laboratory specimens on reported glucose results and diagnosis of clinically significant hypoglycemia (<50 mg/dL) or elevated glucose levels (>100 mg/dL). METHODS: We assessed all fasting-serum glucose tests from the adult population (190 767 subjects) without known diabetes residing in Southern Israel. Before and after intervention periods were compared: 268 359 blood tests were performed during 2009-2010, and 317 336 during 2012-2013. RESULTS: While glucose levels were 94.17 mg/dL ± 14.12 in 2012-2013 versus 83.53 mg/dL ± 14.50 in 2009-2010 (12.75% ± 0.88 increase, P < .001), the difference in glycated hemoglobin levels was statistically significant but clinically negligible: 5.84% ± 0.56 in 2012-2013 versus 5.88% ± 0.56 in 2009-2010 (0.53% ± 0.78 decrease, P < .01). There was an increased likelihood of a glucose result to be above 100 mg/dL following intervention: 9.80% versus 25.90%, P < .001. For clinics distanced over 40 km from the laboratory, age-adjusted odds ratio value was 1.26 (95% CI 1.13, 1.41). The proportion of samples with hypoglycemia values decreased from 0.33% to 0.03% (P < .001). CONCLUSIONS: We demonstrated an important change in glucose values over a two-year period following an improvement of the preanalytic processes. The intervention was related to an increase in the frequency of hyperglycemia results and a decrease in the number of hypoglycemia results. Future administrative projects should consider clinical consequences with involvement of all relevant stakeholders.

[Mastering the analytical process of the Complete Blood Count: how and why?] / Maîtrise du processus analytique de la Numération Formule Sanguine : comment et pourquoi ?

This is a prospective study realized at the level of the hematology department and blood transfusion center of the University Hospital Center (CHU) of Dr Ben Badis of Constantine and spread out over a period of one year (from January 1st to December 31st). The work focused on the analytical processes mastery of the NFS needs a compulsory step concerning technical and organizational laboratory skills respecting the ISO 15189 laws going through a mastery of support processes (humain resourses, informatics, materials, documents, management) indispensable for the good function of analytic proceedings, a performance evaluation of the hematology analyzer Advia (2120 I and II and 560) and quality control management (intern, extern). The analytic performance evaluation of Advia gives reliable results reproductible and stable for use of the routine automatisation good inter-machine correlation and laboratory performance in terms of the quality extern evaluation with military hospital laboratory.

[Recommendations for acylcarnitine profile analysis]. / Recommandations concernant l'analyse du profil des acylcarnitines.

Biochemical diagnosis of hereditary metabolic diseases requires the detection and simultaneous identification of a large number of compounds, hence the interest in metabolic profiles. Acylcarnitine profile allows the identification and quantification of more than thirty compounds. As part of the accreditation process for medical biology examinations according to standard NF EN ISO 15189, the group from SFEIM recommends an approach to accredit acylcarnitine profile. Validation parameters and recommendations are discussed in this specific framework.

[Improvement of the pre-examination phase of medical biology exams at the Henri Mondor University Hospitals: a pilot study]. / Une étude pilote pour l'amélioration de l'étape pré-analytique des examens de biologie médicale pris en charge au sein des hôpitaux universitaires Henri Mondor.

The medical and university department of biology pathology at Henri Mondor hospital in Créteil has been engaged in an NF EN ISO 15189 accreditation process since 2014. One of the elements of this process concerns the quality of handling of samples and their transportation to laboratories, including the implementation place requires fighting against pre-examination non-conformities, which are the source of many dysfunctions. The pre-examination group has implemented several actions in a targeted care service. Thanks to these, the rate of non-conformities has halved in 18 months. In parallel, a work project targeting student nurses on internship was born to follow up on the results of a statistical study carried out by the pre-examination group on non-conformities. The objective of the project was to include nursing students on internship in a full support course on good sampling practices and pre-analytical non-conformities. This was based on the realization of two knowledge quizzes (before and after training), theoretical training, and visits to several laboratories. This study lasted 10 months with the participation of 37 students. The results showed a marked improvement in knowledge of pre-analytics as well as total satisfaction of all students. Our approach has helped to better understand the needs of laboratories and demonstrates the usefulness of training students in good sampling practices in order to ensure better patient care as well as an improvement in their comfort and well-being.

[How did the private labs fit onto COVID-19 crisis?] / Comment les laboratoires de biologie médicale privés français se sont adaptés à la crise de la COVID-19 ?

Confronted with the COVID-19 crisis, healthcare professionals have had to tackle an epidemic crisis of a huge magnitude for which they were not prepared. Medical laboratories have been on the front line, from collecting samples to performing the analysis required to diagnose this new pathology. Responding to the needs and to the urgency of the situation, the authorities relied on the network of private laboratories. In France, private laboratory medicine represents 70% of overall activity, and with a network of more than 4,000 local laboratories, private laboratory medicine has been the cornerstone of the « screen-trace-isolate ¼ strategy. This article gives feedback from private laboratory medicine professionals, directly involved in the reorganization carried out at the pre-analytical, analytical and post-analytical stages, during the crisis from March to October 2020.

Blood sampling guidelines with focus on patient safety and identification - a review.

It has been well documented over recent years that the preanalytical phase is a leading contributor to errors in the total testing process (TTP). There has however been great progress made in recent years due to the exponential growth of working groups specialising in the field. Patient safety is clearly at the forefront of any healthcare system and any reduction in errors at any stage will improve patient safety. Venous blood collection is a key step in the TTP, and here we review the key errors that occur in venous phlebotomy process and summarise the evidence around their significance to patient safety. Recent studies have identified that patient identification and tube labelling are the steps that carry the highest risk with regard to patient safety. Other studies have shown that in 16.1% of cases, patient identification is incorrectly performed and that 56% of patient identification errors are due to poor labelling practice. We recommend that patient identification must be done using open questions and ideally three separate pieces of information. Labelling of the tube or linking the identity of the patient to the tube label electronically must be done in the presence of the patient whether it is before or after sampling. Combined this will minimise any chance of patient misidentification.

Sample transportation - an overview.

Transportation of blood samples is a major part of the preanalytical pathway and can be crucial in delaying laboratory results to the clinicians. A variety of aspects however makes sample transportation a complex, challenging and often overlooked task that needs thorough planning and dedicated resources. The purpose of this review is to outline the options available for this task and to emphasize the preanalytical aspects that need consideration in this process, e.g. performance specifications for sample transportation as stated in ISO standards 15189 and 20658, quality control of automated transportation systems, monitoring of sample integrity parameters and temperature surveillance in general and for external samplers in particular. All these are tasks that the laboratory must assure on a daily basis in terms of continuous quality control, and simultaneously the laboratory must remain alert to alterations in clinical demands (sample frequency, turn-around-times) and new regulations within this area (e.g. the recent General Data Protection Regulation from the EU).

Blood sample quality.

Several lines of evidence now confirm that the vast majority of errors in laboratory medicine occur in the extra-analytical phases of the total testing processing, especially in the preanalytical phase. Most importantly, the collection of unsuitable specimens for testing (either due to inappropriate volume or quality) is by far the most frequent source of all laboratory errors, thus calling for urgent strategies for improving blood sample quality and managing data potentially generated measuring unsuitable specimens. A comprehensive overview of scientific literature leads us to conclude that hemolyzed samples are the most frequent cause of specimen non-conformity in clinical laboratories (40-70%), followed by insufficient or inappropriate sample volume (10-20%), biological samples collected in the wrong container (5-15%) and undue clotting (5-10%). Less frequent causes of impaired sample quality include contamination by infusion fluids (i.e. most often saline or glucose solutions), cross-contamination of blood tubes additives, inappropriate sample storage conditions or repeated freezing-thawing cycles. Therefore, this article is aimed to summarize the current evidence about the most frequent types of unsuitable blood samples, along with tentative recommendations on how to prevent or manage these preanalytical non-conformities.

Preanalytical aspects on short- and long-term storage of serum and plasma.

Following an ordered clinical chemistry plasma/serum test, ideally the venous blood specimen is adequately collected at a health care facility, then swiftly transported to and readily handled, analyzed and sometimes interpreted at a clinical chemistry laboratory followed by a report of the test result to the ordering physician to finally handle the result. However, often there are practical as well as sample quality reasons for short- or long-term storage of samples before and after analysis. If there are specific storage needs, the preanalytical handling practices are specified in the laboratory's specimen collection instructions for the ordered test analyte. Biobanking of specimens over a very long time prior to analysis includes an often neglected preanalytical challenge for preserved quality of the blood specimen and also involves administrative and additional practical handling aspects (specified in a standard operating procedure - SOP) when demands and considerations from academic, industry, research organizations and authorities are included. This short review highlights some preanalytical aspects of plasma/serum short- and long- term storage that must be considered by clinicians, laboratory staff as well as the researchers.