By Denise Baez; DG  Alerts Covid 19

 
NEW YORK -- September 16, 2020 -- The Infectious Diseases Society of America (IDSA) has published evidence-based recommendations to assist clinicians, clinical laboratories, patients, and policymakers in decisions related to the optimal use of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic tests in a variety of settings.

The guideline, published in Clinical Infectious Diseases, is the fourth in a series of rapid, frequently updated coronavirus disease 2019 (COVID-19) guidelines developed by IDSA. The guideline panel, composed of clinicians and clinical microbiologists, used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach for evidence assessment, and agreed on 8 diagnostic recommendations:

The IDSA panel suggests against using serologic testing to diagnose SARS-CoV-2 infection during the first 2 weeks (14 days) following symptom onset (conditional recommendation, very low certainty of evidence).

When SARS-CoV-2 infection requires laboratory confirmation for clinical or epidemiological purposes, the IDSA panel suggests testing for SARS-CoV-2 IgG or total antibody 3 to 4 weeks after symptom onset to detect evidence of past SARS-CoV-2 infection (conditional recommendation, very low certainty of evidence).

When serology is being considered as an adjunct to nucleic acid amplification tests for diagnosis, testing 3 to 4 weeks post-symptom onset maximises the sensitivity and specificity to detect past infection.

Serosurveillance studies should use assays with high specificity, especially when the prevalence of SARS-CoV-2 in the community is expected to be low (?1%).

The IDSA panel makes no recommendation either for or against using IgM antibodies to detect evidence of past SARS-CoV-2 infection (conditional recommendation, very low certainty of evidence).

The IDSA panel suggests against using IgA antibodies to detect evidence of past SARS-CoV-2 infection (conditional recommendation, very low certainty of evidence).

The IDSA panel suggests against using IgM or IgG antibody combination tests to detect evidence of past SARS-CoV-2 infection (conditional recommendation, very low certainty of evidence).

IgM or IgG combination tests are those where detecting either antibody class is used to define a positive result.

The IDSA panel suggests using IgG antibody to provide evidence of COVID-19 infection in symptomatic patients with a high clinical suspicion and repeatedly negative NAAT testing (weak recommendation, very low certainty of evidence).

When serology is being considered as an adjunct to NAAT for diagnosis, testing 3 to 4 weeks post-symptom onset maximises the sensitivity and specificity to detect past infection.

In paediatric patients with multisystem inflammatory syndrome, the IDSA panel suggests using both IgG antibody and NAAT to provide evidence of current or past COVID-19 infection (strong recommendation, very low certainty of evidence).

The IDSA panel makes no recommendation for or against using capillary versus venous blood for serologic testing to detect SARS-CoV-2 antibodies (knowledge gap).

“Based on the available evidence at this time, serologic tests should not be used to determine immunity or risk of re-infection,” the panel wrote. “Thus, antiSARS-CoV-2 antibody detection cannot inform decisions to discontinue physical distancing or lessen the use of personal protective equipment.”

“It is important to realise that guidelines cannot account for individual variation among patients,” the panel noted. “They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of a patient’s individual circumstances.”

Reference: https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1343/5904785

SOURCE: Clinical Infectious Diseases