At Home Testing: What About False Positives or Negatives? What About Accuracy?

Thinking of taking an at-home test and skipping the doctor’s office? Think twice, and consult a healthcare provider when you get the results.

René F. Najera, MPH, DrPH
6 min readSep 15, 2023
COVID-19 rapid antigen test showing positive result with two lines, one at the ‘C’ (control) position and one at the ‘T’ (test) position.
Is this result reliable?

You’re at home, and you’re worried you’re infected with some virus, like influenza or the novel coronavirus that triggered the COVID-19 pandemic. You don’t have cash for the doctor’s visit, but you did see an at-home test at the pharmacy. You decide to buy the $20 test, and go from there. The test is 99% sensitive and 99% specific, according to the packaging.

But how accurate is it?

The answer to this question is always, “It depends…” Some lengthy explanation follows this answer of what is best for the person being tested. When it comes to individual medical decisions, these discussions are best when had by a healthcare provider and the patient, not the patient and Google. That’s changing, though. And we in public health are coming to terms with people doing at-home testing and not reporting those results to public health.

Reporting to public health is essential, though.

Take, for example, influenza surveillance. When I started working at a state health department, one of the…



René F. Najera, MPH, DrPH

DrPH in Epidemiology. Public Health Instructor. Father. Husband. "All around great guy."