9/23—Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Serologic Testing
A multidisciplinary panel of infectious diseases clinicians […] identified and prioritized clinical questions related to the use of SARS-CoV-2 serologic tests. The panel agreed on eight diagnostic recommendations. The panel identified three potential indications for serologic testing including: 1) evaluation of patients with a high clinical suspicion for COVID-19 when molecular diagnostic testing is negative and at least two weeks have passed since symptom onset; 2) assessment of multisystem inflammatory syndrome in children; and 3) for conducting serosurveillance studies. The certainty of available evidence supporting the use of serology for either diagnosis or epidemiology was graded as very low to moderate (Hanson et al. 2020).
Evaluation of the performance of SARS-CoV-2 serological tools and their positioning in COVID-19 diagnostic strategies
We assessed 2 immunochromatographic lateral flow assays and 2 enzyme-linked immunosorbent assay kits using serum samples from PCR-confirmed COVID-19 hospitalized patients (n = 55) and healthcare workers (n = 143) and 127 samples from negative controls. Clinical sensitivities varied greatly among the assays, showing poor mutual agreement. A thorough selection of serological assays for the detection of ongoing or past infections is advisable.
Pooled Testing for Surveillance of SARS-CoV-2 in Asymptomatic Individuals
A total of 700 pools (7000 individual specimens) were tested using the Panther assay (n = 332) and the CDC assay (n = 368). Eight positive pools were detected, equivalent to 0.11% positivity rate in asymptomatic healthcare workers. Every positive pool yielded only one positive specimen upon deconvolution. We conclude that 10-specimen manual pooling algorithm maintaining a unidirectional workflow is effective for surveillance testing of SARS-CoV-2 in asymptomatic healthcare workers.
Measurement of SARS-CoV-2 RNA in wastewater tracks community infection dynamics
We measured SARS-CoV-2 RNA concentrations in primary sewage sludge in the New Haven, Connecticut, USA, metropolitan area. SARS-CoV-2 RNA concentrations in sludge were 0–2 d ahead of SARS-CoV-2 positive test results by date of specimen collection, 0–2 d ahead of the percentage of positive tests by date of specimen collection, 1–4 d ahead of local hospital admissions and 6–8 d ahead of SARS-CoV-2 positive test results by reporting date. Our data show the utility of viral RNA monitoring in municipal wastewater for SARS-CoV-2 infection surveillance at a population-wide level. In communities facing a delay between specimen collection and the reporting of test results, immediate wastewater results can provide considerable advance notice of infection dynamics.
Wastewater-based epidemiology for COVID-19 – approaches and challenges for surveillance and prediction
The presence of viral RNA within wastewater, regardless of viral infectivity, constitutes an indirect population-level diagnostic tool. Sampling for wastewater-based epidemiology applications offers both spatial and temporal challenges that can compromise the degree to which the resulting data is “representative” of the study population (Fig. 1).
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