Lessons in diagnostic virology: expected and unexpected sources of error

Abstract

Viral diagnostics have shown continued innovation, with serological and molecular diagnostic assays pushing the limits of sensitivity. Technology has provided new automated shared diagnostic platforms that reduce hands-on time, while with globalisation of the diagnostic market, commercial assays are applied across epidemiologically diverse settings on different patient and viral populations. However, with these novel developments, new and often unexpected sources of diagnostic error emerge. In this review we will reflect on case studies that highlight these often underappreciated or unexpected diagnostic errors spanning pre-analytical, analytical, and post-analytic processes. We will also suggest approaches that could help identify error and reduce the impact on patient management.

Challenges in Laboratory Diagnosis of the Novel Coronavirus SARS-CoV-2

“…It is estimated that more than one-fourth of all pre-analytical errors result in an unnecessary investigation or inappropriate patient care, substantially magnifying the financial burden on the healthcare system [24], and thus resulting in inadequate and slow healthcare. The safety and quality of diagnostic testing may be endangered by misidentification of the patient and/or sample, collection of an inappropriate or insufficient sample, inaccurate conditions of sample transportation and storage (e.g., prolonged transportation time and injury exposure), presence of interfering substances (e.g., cellular components due to whole blood freezing and inappropriate additives) [25][26][27], and finally, procedural issues occurring during sample preparation, including pipetting errors during manual sample preparation or aliquoting, cross-contamination and sample mismatch [28]. Although analytical errors are believed to be the smallest contributors to laboratory errors, there are several potential analytical problems that could significantly jeopardize the quality of testing, and thus need to be considered.…”

“…Although analytical errors are believed to be the smallest contributors to laboratory errors, there are several potential analytical problems that could significantly jeopardize the quality of testing, and thus need to be considered. Analytical errors include equipment malfunction, non-adequately validated assays, undetected failure of quality control, active viral recombination, testing carried outside the diagnostic window, poor harmonization of primers or probes, and non-specific rRT-PCR annealing, along with other technical issues [25][26][27].…”

Intervalo de tempo decorrido entre o início dos sintomas e a realização do exame para COVID-19 nas capitais brasileiras, agosto de 2020*

“…This can cause unnecessary investigation and, consequently, increase the financial burden on the health system and result in inadequate and slow health care, according to reviews conducted in Qatar and South Africa. 25,26 The limitations of this study relate to recording of dates, in particular uncertainty as to symptom onset, and the high number of incomplete records on the e-SUS Notifica system, resulting in losses in the sample studied. However, we believe that these losses did not interfere in the results found.…”

Renewed Focus on the Threat of Cross-Contamination in Molecular Laboratories: Notes from the COVID-19 Testing Experience in Bangladesh

“…To ensure that the process is free of contamination, no amplification must be detected in the negative controls provided by the test kit, as well as in the elution buffer (or whatever is appropriate depending on the test kit used). In the event of possible contamination, the quality of the water should be verified, and contamination of the instrument should be considered in some circumstances [25].…”