COVID-19: Diagnostic Accuracy of Current Serological Tests Not Good Enough

Priscilla Lynch 

July 09, 2020

Current evidence does not support continued use of existing point-of-care serological tests for COVID-19, concludes a new systematic review and meta-analysis in the BMJ.

Researchers searched Medline, bioRxiv and medRxiv from 1 January 2020 to 30 April 2020 for studies related to COVID-19 and serological tests.

Eligible studies measured sensitivity, specificity or both of a COVID-19 serological test compared with a reference standard of viral culture or reverse transcriptase polymerase chain reaction. Risk of bias was assessed using quality assessment of diagnostic accuracy studies 2 (QUADAS-2). Pooled sensitivity and specificity were estimated using random effects bivariate meta-analyses.

A total of 5014 references were identified, and 40 studies were included.

High risk of patient selection bias was found in 98 per cent (48/49) of assessments and high or unclear risk of bias from performance or interpretation of the serological test in 73 per cent (36/49). Only 10 per cent (4/40) of studies included outpatients. Only two studies evaluated tests at the point of care.

For each method of testing, pooled sensitivity and specificity were not associated with the immunoglobulin class measured. The pooled sensitivity of enzyme linked immunosorbent assays (ELISAs) measuring immunoglobulin G or immunoglobulin M was 84.3 per cent (95% CI, 75.6%-90.9%), of lateral flow immunoassays (LFIAs) was 66.0 per cent (95% CI, 49.3%-79.3%) and of chemiluminescent immunoassays (CLIAs) was 97.8 per cent (95% CI, 46.2%-100%).

In all analyses, pooled sensitivity was lower for LFIAs, the potential point-of-care method. Pooled specificities ranged from 96.6 per cent to 99.7 per cent. Of the samples used for estimating specificity, 83 per cent (10,465/12,547) were from populations tested before the epidemic or not suspected of having COVID-19. Among LFIAs, pooled sensitivity of commercial kits (65.0%; 95% CI, 49.0%-78.2%) was lower than non-commercial tests (88.2%; 95% CI, 83.6%-91.3%).

Heterogeneity was seen in all analyses. Sensitivity was higher for at least three weeks after symptom onset (range, 69.9%-98.9%) compared with within the first week (from 13.4% to 50.3%).

Higher-quality clinical studies assessing the diagnostic accuracy of COVID-19 serological tests are urgently needed, the researchers said.

Lisboa Bastos M, Tavaziva G, Abidi SK, Campbell JR, Haraoui LP, Johnston JC, Lan Z, Law S, MacLean E, Trajman A, Menzies D, Benedetti A, Ahmad Khan F. Diagnostic accuracy of serological tests for covid-19: systematic review and meta-analysis. BMJ. 2020;370:m2516. doi: 10.1136/bmj.m2516. PMID: 32611558.  Full text.

This article originally appeared on Univadis, part of the Medscape Professional Network.

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