For less than two dollars you can buy a home test kit for strep throat, and save yourself the trouble of going to urgent care or your pediatrician. But how accurate are home step throat tests? Is it worth it?
The Medchoice Strep A Rapid Test Kit by BTNX sells on Amazon for about $40 for a box of 25 tests. The company claims their test is very accurate, with a sensitivity of 97% and a specificity of 95%. This means there is a low false negative rate and a low false positive rate. The test has been cleared by the FDA and results are ready within 5 minutes. So what’s a parent got to lose? Why go to the doctor if your child has a sore throat?
Children are at higher risk than adults for serious health consequences from group A streptococcal infections, including rheumatic heart disease and a kidney disease called glomerulonephritis. Hence, in pediatrics we are more careful not to miss the diagnosis due to a false negative rapid strep test. We don’t have a better or fancier test in our office or hospital than the ones you can buy online– we actually do two different tests.
In pediatrics, when we test for strep in an office or hospital we actually run two different tests– a rapid strep test (which is the test described above) and a culture test. For the culture test, the specimen swab is rubbed on a petri dish of agar (bacteria food) and put in an incubator to grow. If group A streptococcal bacteria grow on the agar, we say the culture is positive. The culture test is the most accurate test for strep throat. Every negative rapid step test is “backed up” with a culture test so that we don’t miss the diagnosis.
Home strep testing can still save a tired parent time and grief. If the test is positive, you’ve got an answer for why your child is sick. You need to contact your doctor and get a prescription for antibiotics. Early treatment of strep throat with antibiotics prevents the serious complications of strep and helps your child feel better quickly. Sometimes a home strep test can help you decide if you should go to the pediatrician today or wait until tomorrow to see if they are worse. It can help you decide if you need to keep your child home tomorrow and allow you to rearrange your family plans, find childcare, etc.
The problem is what to do when a home rapid strep test is negative. Your child really should be seen by your doctor anyway to get a back-up culture test. If you just wait a few days to see if your child gets worse, it may be too late to prevent the rare but serious consequences of group A streptococcal infection.
If the rapid strep test is negative, we still need to figure out what is wrong with your child. Is it the flu? We can test for that in the office, too. You can buy a home flu test online, but they are expensive, about $200 for 15 test kits. Influenza can be treated, but the antiviral medicine is most effective if started within 24 hours of the onset of symptoms. So if you wait too long to get tested, treatment is unlikely to be effective.
I get it– going to the doctor, paying your copay and waiting to be seen is no fun for any busy family, especially when your kids are sick. But whether your home strep test is positive or negative, your child still needs to be seen by their pediatrician.