The Royal College of Pathologists of Australasia (RCPA) advises against the use of serological COVID-19 IgG/IgM rapid tests, such as a pin prick blood test, to detect early COVID disease.
RCPA says the IgG/IgM tests have a fundamental limitation, as they rely on the detection of antibodies made by the patient in response to SARS-COV-2. They do not detect the virus.
Patients may only make antibodies to COVID-19 infection a week to 12 days after they first become sick. If doctors rely on these rapid tests early in the disease, RCPA says their diagnosis will be wrong.
RCPA states that:
- Molecular testing on a single throat with deep nasal swab is the current test of choice for the diagnosis of acute COVID 19 infection.
- COVID-19 IgG/IgM rapid tests have no role to play in the acute diagnosis of COVID-19 virus infection.
- COVID-19 IgG/IgM rapid tests will miss patients in the early stages of disease when they are infectious to other people.