My daughter is on penicillin for tonsillitis. She has had a negative COVID-19 test result which is surprising because my son is positive for COVID-19 and she has all the COVID-19 symptoms. Is it possible that being on penicillin has produced a false negative result for COVID-19 when it should have been positive?
It is highly unlikely that the penicillin has interfered with the COVID-19 test as it only affects bacteria, not viruses. However, more information is being published about specificity and sensitivity of COVID-19 tests. That essentially measures how accurate the testing is – and recent information suggests that there can be reasonable incidence of False Negative tests occurring in those who actually have COVID-19. A BMJ article has reinforced a key message that “a single negative COVID-19 test should not be used as a rule-out in patients with strongly suggestive symptoms”. The more important action is to isolate and follow the usual guidance if you believe she (or anyone in the household) has COVID-19 symptoms.