Sodium citrate blood contamination by K2-ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing

Pre-analytical errors in coagulation testing: a case series

OBJECTIVES

Prevention of pre-analytical issues in coagulation testing is of paramount importance for good laboratory performance. In addition to common issues like hemolysed, icteric, or lipemic samples, some specific pre-analytical errors of coagulation testing include clotted specimens, improper blood-to-anticoagulant ratio, contamination with other anticoagulants, etc. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are very commonly affected tests due to pre-analytical variables. The impact these parameters possess on surgical decision-making and various life-saving interventions are substantial therefore we cannot afford laxity and casual mistakes in carrying out these critical investigations at all.

CASE PRESENTATION

In this case series, a total of 4 cases of unexpectedly deranged coagulation profiles have been described which were reported incorrectly due to the overall casual approach towards these critical investigations. We have also mentioned how the treating clinician and lab physician retrospectively accessed relevant information in the nick of time to bring back reassurance.

CONCLUSIONS

Like every other critical investigation, analytical errors can occur in coagulation parameters due to various avoidable pre-analytical variables. The release of spurious results for coagulation parameters sets alarm bells ringing causing much agony to the treating doctor and patient. Only a disciplined and careful approach taken by hospital and lab staff towards each sample regardless of its criticality can negate these stressful errors to a large extent.

Accuracy of Citrate Anticoagulant Amount, Volume, and Concentration in Evacuated Blood Collection Tubes Evaluated with UV Molecular Absorption Spectrometry on a Purified Water Model

Citrate anticoagulant concentration affects the results of coagulation tests. Until now, the end user had no direct insight into the quality of evacuated blood collection tubes. By introducing an easy-to-perform UV spectrometric method for citrate determination on a purified water model, we enabled the evaluation of (1) the accuracy of the anticoagulant amount added into the tubes by a producer, (2) the accuracy of the volume of anticoagulant solution in the tube at the instant of examination, (3) the anticoagulant concentrations at a draw volume. We examined the Vacuette^®, Greiner BIO-ONE, Vacutube, LT Burnik d.o.o., and BD Vacutainer^® tubes. The anticoagulant amount added into the tubes during production had a relative bias between 3.2 and 23.0%. The anticoagulant volume deficiency at the instant of examination expressed as a relative bias ranged between -11.6 and -91.1%. The anticoagulant concentration relative bias after the addition of purified water in a volume that equalled a nominal draw volume extended from 9.3 to 25.7%. Draw-volume was mostly compliant during shelf life. Only Vacutube lost water over time. Contamination with potassium, magnesium, or both was observed in all the tubes but did not exceed a 0.21 mmol/L level. This study enables medical laboratories to gain insight into the characteristics of the citrate blood collection tubes as one of the preanalytical variables. In situations that require anticoagulant adjustment for accurate results, this can help make the right decisions. The methodology gives producers additional means of controlling the quality of their production process.

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.

Clot activators and anticoagulant additives for blood collection. A critical review on behalf of COLABIOCLI WG-PRE-LATAM

In the clinical laboratory, knowledge of and the correct use of clot activators and anticoagulant additives are critical to preserve and maintain samples in optimal conditions prior to analysis. In 2017, the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) commissioned the Latin American Working Group for Preanalytical Phase (WG-PRE-LATAM) to study preanalytical variability and establish guidelines for preanalytical procedures to be applied by clinical laboratories and health care professionals. The aim of this critical review, on behalf of COLABIOCLI WG-PRE-LATAM, is to provide information to understand the mechanisms of the interactions and reactions that occur between blood and clot activators and anticoagulant additives inside evacuated tubes used for laboratory testing. Clot activators - glass, silica, kaolin, bentonite, and diatomaceous earth - work by surface dependent mechanism whereas extrinsic biomolecules - thrombin, snake venoms, ellagic acid, and thromboplastin - start in vitro coagulation when added to blood. Few manufacturers of evacuated tubes state the type and concentration of clot activators used in their products. With respect to anticoagulant additives, sodium citrate and oxalate complex free calcium and ethylenediaminetetraacetic acid chelates calcium. Heparin potentiates antithrombin and hirudin binds to active thrombin, inactivating the thrombin irreversibly. Blood collection tubes have improved continually over the years, from the glass tubes containing clot activators or anticoagulant additives that were prepared by laboratory personnel to the current standardized evacuated systems that permit more precise blood/additive ratios. Each clot activator and anticoagulant additive demonstrates specific functionality, and both manufacturers of tubes and laboratory professional strive to provide suitable interference-free sample matrices for laboratory testing. Both manufacturers of in vitro diagnostic devices and laboratory professionals need to understand all aspects of venous blood sampling so that they do not underestimate the impact of tube additives on laboratory testing.

Unexpected abnormal coagulation test results in a 2-year-old child: A case report

Rejection of the sample with repeated blood withdrawal is always an unwanted consequence of sample nonconformity and preanalytical errors, especially in the most vulnerable population - children. Here is presented a case with unexpected abnormal coagulation test results in a 2-year-old child with no previously documented coagulation disorder. Child is planned for tympanostomy tubes removal under the anaesthesia driven procedure, and preoperative coagulation tests revealed prolonged prothrombin time, activated partial thromboplastin time and thrombin time, with fibrinogen and antithrombin within reference intervals. From the anamnestic and clinical data, congenital coagulation disorder was excluded, and with further investigation, sample mismatch, clot presence and accidental ingestion of oral anticoagulant, heparin contamination or vitamin K deficiency were excluded too. Due to suspected EDTA carryover during blood sampling another sample was taken the same day and all tests were performed again. The results for all tests were within reference intervals confirming EDTA effect on falsely prolongation of the coagulation times in the first sample. This case can serve as alert to avoid unnecessary loss in terms of blood withdrawal repetitions and discomfort of the patients and their relatives, tests repeating, prolonging medical procedures, and probably delaying diagnosis or proper medical treatment. It is the responsibility of the laboratory specialists to continuously educate laboratory staff and other phlebotomists on the correct blood collection as well as on its importance for the patient's safety.

Faba bean protein flours added to pasta reduce post-ingestion glycaemia, and increase satiety, protein content and quality

Durum Wheat Semolina (DWS) pastas with added fababean (FB) protein flour reduce postprandial blood glucose and appetite and have higher nutritional quality.

A national survey of specimen contamination in the UK

BACKGROUND

Specimen contamination that goes unnoticed can have many adverse consequences for patients including inappropriate investigations or treatment decisions based on erroneous results. Little is known about UK laboratory practices relating to specimen contamination; therefore, this national survey aimed to gather valuable baseline data.

METHODS

An electronic survey consisting of 26 questions was designed to obtain key information relating to specimen contamination including its frequency, how it is identified by laboratories and actions taken in event of confirmed contamination. The survey was circulated to Heads of Departments of all NHS laboratories in the UK.

RESULTS

Fifty-two responses (15%) were received from 353 laboratories surveyed. Recording and extracting specimen contamination data from laboratory IT systems appear to be a challenge for many laboratories. There is potentially a lack of awareness of correct order of draw for venous blood collection which is a factor known to contribute to contamination. There is wide variation in contamination rates (EDTA, citrate and drip arm), and the methods laboratories use to identify it which often rely on professional judgement. Similarly, there is little consensus among senior laboratory professionals on how best to report results on contaminated samples, and record events in risk management systems.

CONCLUSIONS

There is a need for greater consensus on laboratories' approach to specimen contamination, particularly around mechanisms to identify and monitor it, and follow up actions. We make several recommendations to facilitate improvements it this area; however, there is a need to develop consensus guidelines which can aid both clinicians and laboratories.

Case report of unexplained hypocalcaemia in a slightly haemolysed sample

The case presented highlights a common pre-analytical problem identified in the laboratory that was initially missed. It concerns a young, generally healthy adult patient with no significant medical history and no significant family history. They presented with common flu like symptoms to their primary care clinician who considered this was most likely a viral problem that would pass with time. The clinician, however, did some routine bloods to reassure the patient despite a lack of clinical indication. When the sample was analysed the sample was haemolysed with strikingly low calcium. This led to the patient being called into hospital for urgent repeat investigations, all of which turned out to be within normal ranges. On further investigation the original sample was found to be contaminated. This result would normally have been flagged but was missed due to the complication of haemolysis.

Pre-analytical phase management: a review of the procedures from patient preparation to laboratory analysis

The pre-analytical phase encompasses all the procedures before the start of laboratory testing. This phase of the testing process is responsible for the majority of the laboratory errors, since the related procedures involve many sorts of non-laboratory professionals working outside the laboratory setting, thus without direct supervision by the laboratory staff. Therefore, either correct organization or management of both personnel and procedures that regard blood specimen collection by venipuncture are of fundamental importance, since the various steps for performing blood collection represent per se sources of laboratory variability. The aim of this (non-systematic) review addressed to healthcare professionals is to highlight the importance of blood specimen management (from patient preparation to laboratory analyses), as a tool to prevent laboratory errors, with the concept that laboratory results from inappropriate blood specimens are inconsistent and do not allow proper treatment nor monitoring of the patient.

Effect of various anticoagulants on the bioanalysis of drugs in rat blood: implication for pharmacokinetic studies of anticancer drugs

BACKGROUND

Pharmacokinetic studies are vital in development and optimization of drugs. While blood samples can be collected either in EDTA, heparin or citrate containing tubes for the estimation of drug levels in plasma, EDTA tubes are more commonly used. The purpose of this study was to evaluate the effects of anticoagulants on bioanalysis of drugs. Six drugs used extensively in cancer therapy were selected. Albino wistar rats (N = 6 per drug) were dosed with one of the following drugs intraperitoneally-pemetrexed (50 mg/kg), imatinib (50 mg/kg), erlotinib (25 mg/kg), meropenem (60 mg/kg), 6-mercaptopurine (20 mg/kg) and voriconazole (6 mg/kg). Blood samples were collected 2 h after dosing (1 h in 6-mercaptopurine group due to short half-life) by terminal bleeding from the retro-orbital plexus. Blood was collected in each of Disodium ETDA, heparin, trisodium citrate (TSC) and no anticoagulant (plain) tubes. Drug levels in these samples were determined by validated HPLC assays. ANOVA with Tukey's post hoc test was performed to identify statistically significant differences in drug concentrations in anticoagulant tubes. p < 0.05 was considered statistically significant.

RESULTS

Significant differences in concentration between anticoagulant tubes was observed in case of erlotinib (p = 0.013) and meropenem (p = 0.00), while borderline statistical significance for pemetrexed (p = 0.076). TSC tubes overestimated erlotinib levels, heparin tubes underestimated meropenem concentrations and EDTA tubes overestimated pemetrexed concentrations.

CONCLUSIONS

Careful selection of anti-coagulant is necessary for accurate characterization of pharmacokinetics of drugs. Routine use of EDTA tubes may lead to erroneous interpretation of pharmacokinetic data.

Fabrication and characterization of metal stent coating with drug-loaded nanofiber film for gallstone dissolution

Stent insertion and chemical agents of ethylene diamine tetraacetic acid and sodium cholate for dissolving common bile duct stone diseases through extra biliary tract infusion have been believed a relatively effective therapeutics for the clinical symptom. Core-shell nanofibers produced by co-axial electrospinning to deliver chemical drugs, biomacromolecules, genes and even cells have been reported for various advanced drug delivery system and tissue engineering applications. In the present study, poly (lactide-co-ɛ-caprolactone) (PLCL) core-shell nanofiber-coated film of stent, loaded with ethylene diamine tetraacetic acid and sodium cholate in core layer, was fabricated by co-axial electrospinning for treating gallstone disease. Image of laser scanning confocal microscopy and transmission electron microscopy demonstrated core-shell structure of drug-loaded nanofiber. Fourier transform infrared spectra and the thermogravimetric analysis proved ethylene diamine tetraacetic acid and sodium cholate to be successfully loaded in nanofibers. Morphology of nanofibers after a period of degradation still keeps good shape. Drugs can continuously release for around five days, which was proved significant effectiveness for dissolving gallstone. Besides, unobvious cytotoxicity was exhibited from MTT results and cell kept good morphology in vitro research. The present coated stent showed a bright prospect for dissolving the biliary stone.

Phlebotomy, a bridge between laboratory and patient

The evidence-based paradigm has changed and evolved medical practice. Phlebotomy, which dates back to the age of ancient Greece, has gained experience through the evolution of medicine becoming a fundamental diagnostic tool. Nowadays it connects the patient with the clinical laboratory dimension building up a bridge. However, more often there is a gap between laboratory and phlebotomist that causes misunderstandings and burdens on patient safety. Therefore, the scope of this review is delivering a view of modern phlebotomy to "bridge" patient and laboratory. In this regard the paper describes devices, tools and procedures in the light of the most recent scientific findings, also discussing their impact on both quality of blood testing and patient safety. It also addresses the issues concerning medical aspect of venipuncture, like the practical approach to the superficial veins anatomy, as well as the management of the patient's compliance with the blood draw. Thereby, the clinical, technical and practical issues are treated with the same relevance throughout the entire paper.

Pharmacokinetics and pharmacodynamics of intravenous ilaprazole in healthy subjects after single ascending doses

1. Ilaprazole is a novel proton pump inhibitor and this is the first study to investigate the pharmacokinetics, pharmacodynamics and safety of intravenous ilaprazole in healthy volunteers. 2. In this open-label, single-dose, randomized and four-period crossover study, 16 healthy Chinese subjects received ilaprazole 5, 10 or 20 mg intravenously, or 10 mg orally. Serial blood and urine samples were collected and intragastric pH was recorded within 24 h. The percentage time of intragastric pH > 6 was the major index. Safety was assessed throughout the study. 3. Plasma exposure of intravenous ilaprazole increased proportionally over the dose of 5-20 mg. Clearance and volume of distribution were independent of dose. Ilaprazole was not eliminated through urine and the absolute bioavailability was 55.2%. For the intravenous dose of 5, 10, 20 mg, and oral dose of 10 mg, the mean percentages time of intragastric pH > 6 were 47.3%, 52.8%, 68.2% and 47.5%, respectively. 4. Ilaprazole showed linear pharmacokinetics over the dose of 5-20 mg. Intravenous ilaprazole provided rapid onset of action and the potency of effect were exhibited in a dose-dependent manner. Intravenous ilaprazole was safe and well tolerated except for elevated activated partial thromboplastin time (APTT) and prothrombin time (PT).

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.