Potential preanalytical and analytical vulnerabilities in the laboratory diagnosis of coronavirus disease 2019 (COVID-19)

A novel zoonotic coronavirus outbreak is spreading all over the world. This pandemic disease has now been defined as novel coronavirus disease 2019 (COVID-19), and is sustained by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As the current gold standard for the etiological diagnosis of SARS-CoV-2 infection is (real time) reverse transcription polymerase chain reaction (rRT-PCR) on respiratory tract specimens, the diagnostic accuracy of this technique shall be considered a foremost prerequisite. Overall, potential RT-PCR vulnerabilities include general preanalytical issues such as identification problems, inadequate procedures for collection, handling, transport and storage of the swabs, collection of inappropriate or inadequate material (for quality or volume), presence of interfering substances, manual errors, as well as specific aspects such as sample contamination and testing patients receiving antiretroviral therapy. Some analytical problems may also contribute to jeopardize the diagnostic accuracy, including testing outside the diagnostic window, active viral recombination, use of inadequately validated assays, insufficient harmonization, instrument malfunctioning, along with other specific technical issues. Some practical indications can hence be identified for minimizing the risk of diagnostic errors, encompassing the improvement of diagnostic accuracy by combining clinical evidence with results of chest computed tomography (CT) and RT-PCR, interpretation of RT-PCR results according to epidemiologic, clinical and radiological factors, recollection and testing of upper (or lower) respiratory specimens in patients with negative RT-PCR test results and high suspicion or probability of infection, dissemination of clear instructions for specimen (especially swab) collection, management and storage, together with refinement of molecular target(s) and thorough compliance with analytical procedures, including quality assurance

International survey on D-dimer test reporting: a call for standardization

D-dimer is the biochemical gold standard for diagnosing a variety of thrombotic disorders, but result reporting is heterogeneous in clinical laboratories. A specific five-item questionnaire was developed to gain a clear picture of the current standardization of D-dimer test results. The questionnaire was opened online (December 24, 2014-February 10, 2015) on the platform "Google Drive (Google Inc., Mountain View; CA)," and widely disseminated worldwide by newsletters and alerts. A total of 409 responses were obtained during the period of data capture, the largest of which were from Italy (136; 33%), Australia (55; 22%), Croatia (29; 7%), Serbia (26; 6%), and the United States (21; 5%). Most respondents belonged to laboratories in general hospitals (208; 51%), followed by laboratories in university hospitals (104; 26%), and the private sector (94; 23%). The majority of respondents (i.e., 246; 60%) indicated the use of fibrinogen equivalent unit for expressing D-dimer results, with significant heterogeneities across countries and health care settings. The highest prevalence of laboratories indicated they were using "ng/mL" (139; 34%), followed by "mg/L" (136; 33%), and "\ub5g/L" (73; 18%), with significant heterogeneity across countries but not among different health care settings. Expectedly, the vast majority of laboratories (379; 93%) declared to be using a fixed cutoff rather than an age-adjusted threshold, with no significant heterogeneity across countries and health care settings. The results of this survey attest that at least 28 different combinations of measurement units are currently used to report D-dimer results worldwide, and this evidence underscores the urgent need for more effective international joined efforts aimed to promote a worldwide standardization of D-dimer results reporting

Survey on reporting of epithelial cells in urine sediment as part of external quality assessment programs in Brazilian laboratories

Epithelial cells (ECs) are structures regularly observed during urine microscopy analysis. The correct identification of EC subtypes can be useful since renal tubular epithelial cells (RTECs) are clinically relevant. We investigate the urinary ECs report and the judgement of its clinical importance by Brazilian laboratories. A survey with four questions was made available to participants of the Urinalysis External Quality Assessment Program (EQAP) from Controllab. Laboratories composed 3 groups: (1) differentiating ECs subtypes: “squamous”, “transitional” and “RTECs”; (2) differentiating ECs subtypes: “squamous” or “non-squamous” cells; (3) without ECs subtype identification. Participants did not necessarily answer to all questions and the answers were evaluated both within the same laboratory’s category and within different categories of laboratories. A total of 1336 (94%) laboratories answered the survey; Group 1, 119/140 (85%) reported that ECs differentiation is important to the physician and 62% want to be evaluated by EQAP, while in Group 3, 455/1110 (41%) reported it is useful to them, however only 25% want be evaluated by EQAP. Group 2 laboratories 37/51 (73%) reported that the information is important, but only 13/52 (25%) are interested in an EQAP with differentiation of the 3 ECs subtypes. Most of the laboratories do not differentiate ECs in the three subtypes, despite the clinical importance of RTECs. Education of laboratory staff about the clinical significance of urinary particles should be considered a key priority

The impact of venepuncture training on the reduction of pre?analytical blood sample haemolysis rates: A systematic review

BackgroundVenepuncture involves the introduction of a needle into a vein to collect a representative blood sample for laboratory testing. In the pre‐analytical phase, haemolysis (the rupturing of erythrocytes and release of their contents into the extracellular compartment) has safety, quality and cost implications. Training in correct venepuncture practice has the potential to reduce in vitro haemolysis rates, but the evidence for this notion has yet to be synthesised.DesignSystematic review (PRISMA Checklist).MethodsPublished studies on the effectiveness of venepuncture training on haemolysis rates were searched in relevant databases. The McMaster critical appraisal tool was used to assess methodological quality. The GRADE tool was used to evaluate the body of evidence in relation to the research questions. Implementation fidelity was also scrutinised in each study.ResultsEight out of 437 retrieved studies met the inclusion criteria. None were randomised controlled trials (RCT). Between‐study heterogeneity in design, intervention characteristics and the biochemical threshold for haemolysis precluded a meta‐analysis. Post‐training reductions in haemolysis rates of between 0.4%–19.8% were reported in four of the studies, which developed their intervention according to a clear evidence base and included mentoring in the intervention. Rises in haemolysis rates of between 1.3%–1.9% were reported in two studies, while the intervention effect was inconsistent within two other studies.ConclusionThere are no RCTS on the effectiveness of venepuncture training for reducing haemolysis rates, and findings from the existing uncontrolled studies are unclear. For a more robust evidence base, we recommend more RCTs with standardisation of haemolysis thresholds and training‐related factors.Relevance to clinical practiceWhile venepuncture training is an important factor influencing quality of blood sample in clinical practice, more robust evidence is needed to make specific recommendations about training content for reduction of haemolysis rates. Standardisation of haemolysis thresholds would also enable future meta‐analyses

Analytical interference of intravascular contrast agents with clinical laboratory tests: a joint guideline by the ESUR Contrast Media Safety Committee and the Preanalytical Phase Working Group of the EFLM Science Committee

The Contrast Media Safety Committee of the European Society of Urogenital Radiology has, together with the Preanalytical Phase Working Group of the EFLM Science Committee, reviewed the literature and updated its recommendations to increase awareness and provide insight into these interferences

Effects of a simulation-based workshop on nursing students' competence in arterial puncture

Objective: To evaluate whether a short simulation-based workshop in radial artery puncture would improve nursing students’ competence to a level in which they could practise the procedure on a live patient without compromising his safety. Methods: Quasi-experimental one-group pretest-posttest study with 111 third-year nursing students. A 1.5-hour simulation-based workshop was implemented. This included a video-lecture, live demonstrations, selfdirected simulated practice in dyads and individual intermittent feedback. Participants’ skills, knowledge and self-efficacy in arterial puncture were measured before and after attending the workshop. Results: After the intervention, a total of 61.1% of the participants showed the level of competence required to safely practice radial artery puncture on a live patient under supervision. Conclusion: Effective simulation-based training in arterial puncture for nursing students does not necessarily need to be resource-intensive. Well-planned, evidence-based training sessions using low-tech simulators could help educators to achieve good educational outcomes and promote patient safety