To disinfect or not to disinfect that is the question - Procedure when drawing blood for alcohol measurements in Denmark

Swabbing with ethanol to disinfect the skin before venipuncture does not bias measurements of blood ethanol, as previously suspected. International evidence-based theory may not always be successfully integrated into local practices, where old customs may remain. So how are the local protocols for swabbing in practice - if they even do swab? Not disinfecting may risk patient safety. We aim to put a focus on the venipuncture disinfection procedure in practice when measuring blood alcohol for clinical matters and if their procedure refers to a guideline. Specialized biomedical laboratory scientists (BLS) are typically responsible for the phlebotomy procedure in Denmark, thus questionnaires were sent to the relevant BLS in 2020 to map disinfection procedures in all Danish hospitals and affiliated blood draw clinics (n = 58). The response rate was 93% (54/58). We observed an inter-laboratory dissimilarity in swabbing procedures, when measuring blood alcohol: A quarter did not use any disinfectant (26%), while the remaining disinfected with ethanol 55%, isopropanol 13%, and 6% with ethanol/chlorhexidine. Of the five Danish regions, three had a regional guideline (3/5), otherwise the swabbing protocol was locally based. There was a regional difference in disinfecting or not (Chi2 p < 0,0001). Danish protocols do not always parallel international literature and international guidelines. Not applying disinfectant may jeopardize patient safety. Laboratories are encouraged to work with evidence-based practice or follow newest standardized international guidelines.

Clot time ratio (CTR) and relation to treatment outcome in patients with atrial fibrillation treated with Rivaroxaban

BACKGROUND

There are situations where information about the anticoagulant effects of Rivaroxaban could be clinically useful. Methods for measuring Rivaroxaban concentrations are not available at all medical laboratories while the test MRX PT DOAC for measuring the functional effects of Rivaroxaban, in CTR (Clot Time Ratio), can be made available around the clock. The objectives of this study were to investigate CTR in trough and peak samples during Rivaroxaban treatment of atrial fibrillation and to correlate the findings to bleeding episodes.

METHODS

3 trough- and 3 peak samples from 60 patients (30 on 20 mg daily and 30 on 15 mg daily) were analyzed with PT DOAC. Patients were monitored for 20 months, and bleeding and thrombotic events were documented. Descriptive statistics were used to summarize the data and non-parametric t-test for comparison between groups. ROC curves for the prediction of DOAC plasma levels > 50 ng/mL as determined with LC-MS/MS and anti-FXa methods were computed.

RESULTS

There was a significant difference between trough and peak CTR (median CTR 1.33 vs. 3.57, p < 0.001). 28 patients suffered bleeds. Patients on 20 mg Rivaroxaban with bleeds had higher mean peak CTR than patients without bleeds (CTR 4.11 vs. CTR 3.47, p = 0.040). There was no significant difference in mean CTR between patients on 15 mg Rivaroxaban with or without bleeds (CTR 3.81 vs. 3.21, p = 0.803), or when considering all patients (CTR 3.63 vs. 3.56, p = 0.445). Five out of seven patients on Rivaroxaban 20 with mean peak CTR above the dose specific first to third quartile range (Q1-Q3) suffered bleeds, while 7/16 patients with mean peak CTR within, and 1/7 patients with mean peak CTR below the Q1-Q3 suffered bleeds. The area under the ROC curve was > 0.98 at the upper limit of the PT DOAC reference interval and the negative predictive value of PT DOAC for the prediction of DOAC plasma levels > 50 ng/mL was > 0.96.

CONCLUSIONS

The sample size was too low to draw any firm conclusions but is seems that MRX PT DOAC might be a useful laboratory test in situations where the effect of Rivaroxaban needs evaluation.

An international cross-laboratory survey on fish vitellogenin analysis: Methodological challenges and opportunities for best practice

Vitellogenin (VTG) is a biomarker for possible endocrine activity of chemicals acting via the estrogen, androgen, or steroidogenesis pathways. VTG is assessed in standardised fish guideline studies conducted for regulatory safety assessment of chemicals. VTG data can be highly variable leading to concerns for potential equivocal, false positive and/or negative outcomes. Consequently, additional fish testing may be required to address uncertainties in the VTG response, and possibly erroneous/missed identification of endocrine activity. To better understand the technical challenges of VTG assessment and reporting for regulatory purposes, a survey was sent to 27 testing laboratories performing these analyses. The survey results from 16 respondents (6 from the UK, 3 from the USA, and 7 from the EU) were analysed and discussed in a follow-up webinar. High variability in background VTG concentrations was widely acknowledged and thought to be associated with fish batch, husbandry, laboratory practices, and several methodological aspects. These include sample collection and storage, VTG quantification, data handling, and the benchmarks used for data acceptability. Information gathered in the survey provides a basis for improving and harmonizing the measurement of VTG in fish, and an opportunity to reassess the suitability of current acceptability criteria in test guidelines.

Antifungal susceptibility testing practices in mycology laboratories in France, 2018

A survey of mycology laboratories for antifungal susceptibility testing (AFST) was undertaken in France in 2018, to better understand the difference in practices between the participating centers and to identify the difficulties they may encounter as well as eventual gaps with published standards and guidelines. The survey captured information from 45 mycology laboratories in France on how they perform AFST (number of strains tested, preferred method, technical and quality aspects, interpretation of the MIC values, reading and interpretation difficulties). Results indicated that 86% of respondents used Etest as AFST method, with a combination of one to seven antifungal agents tested. Most of the participating laboratories used similar technical parameters to perform their AFST method and a large majority used, as recommended, internal and external quality assessments. Almost all the participating mycology laboratories (98%) reported difficulties to interpret the MIC values, especially when no clinical breakpoints are available. The survey highlighted that the current AFST practices in France need homogenization, particularly for MIC reading and interpretation.

Handling Anomalous Data in the Lab: Students' Perspectives on Deleting and Discarding

This paper presents and discusses empirical results from a survey about the research practice of Danish chemistry students, with a main focus on the question of anomalous data. It seeks to investigate how such data is handled by students, with special attention to so-called 'questionable research practices' (QRPs) where anomalous data are simply deleted or discarded. This question of QRPs is of particular importance as the educational practices students experience may influence how they act in their future professional careers, for instance in research. The ethical evaluation of QRPs however is not univocal. In parts of the literature QRPs are seen as unquestionably bad, while in other parts of the literature certain QRPs are seen as a necessary aspect of scientific practice. Results from the survey of Danish chemistry students shows that many students engage in certain types of questionable practices, and that a large minority of the students have been actively encouraged by their teachers to engage in such practices. The paper discusses to what extent and under what circumstances such instructional practices can be defended and suggests how the instructional practice connected to the handling of anomalous data can be improved.

A Designed Experiment: Polymorphism Analysis of Angiotensin-Converting Enzyme Gene from Human Buccal Epithelial Cells

For medical students, we combine the laboratory practice with clinical applications by developing biochemical and molecular biology experiments. In this experiment, students first collect their own buccal epithelial cells by a noninvasive mouthwash method. Then, they extract genomic DNA and perform polymerase chain reaction (PCR) to amplify angiotensin-converting enzyme (ACE) gene using genomic DNA as a template. Finally, the polymorphism of ACE gene is observed by electrophoresis. Students not only learn the techniques but also acquire knowledge of the ACE gene polymorphism. By establishing the relationship among ACE polymorphism and high blood pressure and myocardial hypertrophy, students should be able to understand the gene polymorphism and its association with susceptibility to disease. This laboratory practice teaching can also stimulate desire to do scientific research. Experimental results from many individuals can help us determine and analyze the fractions of ACE gene types in Chinese cohorts. Such an experiment strongly activates students and provides a solid foundation for the medical students' future research and clinical application. © 2019 International Union of Biochemistry and Molecular Biology, 47(2): 168-174, 2019.

Effect of On-Site Support on Laboratory Practice for Human Immunodeficiency Virus, Tuberculosis, and Malaria Testing

OBJECTIVES

To evaluate the effect of on-site support in improving human immunodeficiency virus (HIV) rapid testing, tuberculosis (TB) sputum microscopy, and malaria microscopy among laboratory staff in a low-resource setting.

METHODS

This cluster randomized trial was conducted at 36 health facilities in Uganda. From April to December 2010, laboratory staff at 18 facilities participated in monthly on-site visits, and 18 served as control facilities. After intervention, 128 laboratory staff were observed performing 587 laboratory tests across three diseases: HIV rapid testing, TB sputum microscopy, and malaria microscopy. Outcomes were the proportion of laboratory procedures correctly completed for the three laboratory tests.

RESULTS

Laboratory staff in the intervention arm performed significantly better than the control arm in correctly completing laboratory procedures for all three laboratory tests, with an adjusted relative risk (95% confidence interval) of 1.18 (1.10-1.26) for HIV rapid testing, 1.29 (1.21-1.40) for TB sputum microscopy, and 1.19 (1.11-1.27) for malaria microscopy.

CONCLUSIONS

On-site support significantly improved laboratory practices in conducting HIV rapid testing, TB sputum microscopy, and malaria microscopy. It could be an effective method for improving laboratory practice, without taking limited laboratory staff away from health facilities for training.

Increased mean corpuscular haemoglobin concentration: artefact or pathological condition?

INTRODUCTION

In daily practice in haematology laboratories, spurious increased MCHC induces an analytical alarm and needs prompt corrective action to ensure delivery of the right results to the clinicians. The aim of this study was to establish a 'decision tree' using the new parameters red blood cells (RBC-O) and haemoglobin (HGB-O) from the Sysmex XN-10 RET obtained by flow cytometry to deliver appropriate results.

METHODS

From 128 unknown patients with MCHC > 365 g/L, all erythrocyte parameters including reticulocyte parameters were measured and analysed in parallel with blood smears, chemistry index and osmolarity. Differences between optical parameters (RBC-O, HGB-O) and usual parameters (RBC, HGB) obtained by impedance and photometry were reported also.

RESULTS

Four groups were defined from observations: -RBC agglutination (n = 22); -optical interference (n = 17); -RBC disease (n = 18); and -others (n = 71). The use of RBC-O and HGB-O permitted efficient correction of the abnormalities when RBC agglutination and/or optical interference were present in 36 of 39 patients. Reticulocyte parameters permitted to elaborate an RBC score that allowed a highly sensitive detection of RBC disease patients (17/18).

CONCLUSION

Based on new parameters, we propose a 'decision tree' that delivers time savings and supports biological interpretation in case of elevated MCHC.

Critical values in hematology

INTRODUCTION

Critical values are life-threatening results that require immediate notification to the patient's healthcare provider. Accreditation bodies require laboratories to establish critical values. A survey of Ontario laboratories was conducted to determine current practice for critical values in hematology.

METHODS

The survey was sent to 182 participants questioning sources for establishing critical values, levels, review frequency, delta checks, and reporting. The survey was completed by laboratory managers, supervisors, technical specialists, senior technologists, and bench technologists working in hematology.

RESULTS

The majority of participating laboratories have established critical values limits for hemoglobin, leukocyte counts, and platelet counts. Most laboratories also include the presence of malaria parasites and blast cells. Some laboratories reported the presence of plasma cells, sickle cells, schistocytes, and spherocytes as critical values. Multiple sources are used for establishing a critical value policy. There was variability for the frequency of critical values review. Rules may differ for a first-time patient sample vs. a repeat patient sample. Delta checks are seldom used to determine whether a result should be called a critical value. Most participants require the individual taking the critical result(s) to read back and confirm that they are directly involved with the patient's care.

CONCLUSION

There is a lack of consensus for critical values reporting in hematology. As critical value reporting is crucial for patient safety, standardization of this practice would be beneficial.