The coronavirus disease (COVID-19) pandemic has placed the clinical laboratory and testing for SARS-CoV-2 front and center in the worldwide discussion of how to end the outbreak. Clinical ...laboratories have responded by developing, validating, and implementing a variety of molecular and serologic assays to test for SARS-CoV-2 infection. This has played an essential role in identifying cases, informing isolation decisions, and helping to curb the spread of disease. However, as the demand for COVID-19 testing has increased, laboratory professionals have faced a growing list of challenges, uncertainties, and, in some situations, controversy, as they have attempted to balance the need for increasing test capacity with maintaining a high-quality laboratory operation. The emergence of this new viral pathogen has raised unique diagnostic questions for which there have not always been straightforward answers. In this commentary, the author addresses several areas of current debate, including (i) the role of molecular assays in defining the duration of isolation/quarantine, (ii) whether the PCR cycle threshold value should be included on patient reports, (iii) if specimen pooling and testing by research staff represent acceptable solutions to expand screening, and (iv) whether testing a large percentage of the population is feasible and represents a viable strategy to end the pandemic.
Gastrointestinal disease is a major cause of morbidity and mortality worldwide, especially among young children and immunocompromised patients. Diarrhea may result from infection with a variety of ...microbial pathogens, including bacteria, viruses, or parasites. Historically, the diagnosis of infectious diarrhea has been made using microscopy, antigen tests, culture, and real-time PCR. A combination of these traditional tests is often required due to the inability to distinguish between infectious etiologies based on the clinical presentation alone. Recently, several multiplex molecular assays have been developed for the detection of gastrointestinal pathogens directly from clinical stool samples. These panels allow for the detection and identification of up to 20 pathogens in as little as 1 h. This review will focus on the multiplex molecular panels that have received clearance from the FDA for the diagnosis of diarrheal disease and will highlight issues related to test performance, result interpretation, and cost-effectiveness of these new molecular diagnostic tools.
Since the beginning of the COVID-19 pandemic, molecular methods (e.g., real-time PCR) have been the primary means of diagnosing the disease. It is now well established that molecular tests can ...continue to detect SARS-CoV-2 genomic RNA for weeks or months following the resolution of clinical illness. This has prompted public health agencies to recommend a symptom- and/or time-based strategy for discontinuation of isolation precautions, which, for hospitalized patients, results in significant use of personal protective equipment. Due to the inability of current molecular diagnostic assays to differentiate between the presence of remnant viral RNA (i.e., noninfectious) and replication-competent (i.e., infectious) virus, there has been interest in determining whether laboratory tests can be used to predict an individual’s likelihood of transmitting the virus to others. This review will highlight what is currently known about the potential for existing assays, such as real-time PCR and antigen tests, to predict active viral infection. In addition, data on the performance of new methods, such as molecular tests targeting viral RNA intermediates (e.g., subgenomic RNA), will be discussed.
The recent development of commercial panel-based molecular diagnostics for the rapid detection of pathogens in positive blood culture bottles, respiratory specimens, stool, and cerebrospinal fluid ...has resulted in a paradigm shift in clinical microbiology and clinical practice. This review focuses on U.S. Food and Drug Administration (FDA)-approved/cleared multiplex molecular panels with more than five targets designed to assist in the diagnosis of bloodstream, respiratory tract, gastrointestinal, or central nervous system infections. While these panel-based assays have the clear advantages of a rapid turnaround time and the detection of a large number of microorganisms and promise to improve health care, they present certain challenges, including cost and the definition of ideal test utilization strategies (i.e., optimal ordering) and test interpretation.
Rapid and accurate laboratory tests are important for the timely diagnosis and treatment of central nervous system infections. The FilmArray meningitis/encephalitis (ME) panel (BioFire Diagnostics, ...Salt Lake City, UT) is an FDA-cleared, multiplex molecular panel that allows the detection of 14 pathogens (bacterial
= 6, viral
= 7, and fungal
= 1 pathogens) from cerebrospinal fluid (CSF). In this study, we evaluated the performance characteristics of the FilmArray ME panel using clinical, residual CSF samples (
= 291) that tested positive by a routine method(s) (e.g., bacterial culture, individual real-time PCR assay) for a pathogen represented on the ME panel. Of note, a subset (
= 76) of the CSF specimens was collected during the prevaccine era and had been characterized as positive for a bacterial pathogen. The FilmArray ME panel demonstrated an overall percent positive agreement (PPA) of 97.5% (78/80) for bacterial pathogens, 90.1% (145/161) for viruses, and 52% (26/50) for
Despite the low overall agreement (52%) between the ME panel and antigen testing for detection of
, the percent positive agreement of the FilmArray assay for
was 92.3% (12/13) when the results were compared directly to the results of routine fungal smear or culture. The FilmArray ME panel offers a rapid (∼60-min), syndrome-based approach for the detection of select meningitis and encephalitis pathogens.
We compared an FDA-cleared rapid (<20 min) PCR assay (Cobas Liat; Roche Diagnostics) to our routine influenza A and B real-time PCR assay (Simplexa Flu A/B & RSV Direct; Focus Diagnostics) using ...respiratory swabs (n = 197). The Cobas Liat influenza A and B assays demonstrated sensitivities of 99.2% (123/124) and 100% (23/23), respectively, while showing a specificity of 100% for each target.
The possibility of seasonality of COVID-19 is being discussed; we show clinical microbiology laboratory data illustrating seasonality of coronaviruses 229E, HKU1, NL63, and OC43. The data shown are ...specific to the 4 studied coronaviruses and may or may not generalize to COVID-19.
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