IDSA Says When to Test for COVID-19 Antibodies

By Reuters Staff

September 29, 2020

(Reuters) - COVID-19 serology tests are widely available but evidence of their usefulness is limited, the Infectious Diseases Society of America (IDSA) said as it unveiled new guidelines in the journal Clinical Infectious Diseases.

Antibodies to the novel coronavirus do not show up in the blood for quite a while after someone becomes infected, so serology tests are unreliable for diagnosing COVID-19 unless a patient has been sick for weeks, according to the guidelines.

The panel of authors, led by Dr. Kimberly Hanson of the University of Utah, listed three instances in which a test for antibodies to the coronavirus would be warranted.

The first is when doctors strongly suspect a patient has COVID-19 but gold-standard diagnostic PCR molecular tests that look for genetic components of the virus have been negative and at least two weeks have passed since the onset of symptoms.

The second is when a child has signs and symptoms of multisystem inflammatory syndrome, a life-threatening condition that has been linked with previous coronavirus infection.

The third is when public health officials conduct serosurveillance studies to track the proportion of the population that has been exposed to the virus.

SOURCE: Clinical Infectious Diseases, online September 12, 2020.