I realize it can be frustrating to figure out when to bring your child with a sore throat into the office for a Strep test. Sadly, there is not a single "oh, THAT means you have Strep!" symptom or sign of illness. Although the classic quick-onset of a sore throat (felt fine then all of a sudden then "wow, my throat hurts!"), fever, headache, and a stomachache 2-5 days after a Strep exposure certainly can be Strep, many of these turn out to still be a viral illness that does not need an antibiotic. Having impressive cold and cough symptoms makes it less likely the child has Strep (but not impossible). In a large study looking at the size of the tonsils, red throat, mucous in the throat or on the tonsils, and palatal petechiae (small pin-point red dots on the back of the roof of the mouth) found that the only finding in your throat that made it more than a 50% chance that someone with it indeed had Strep was the palatal petechiae. It turned out that 80% (but not 100%!) of those kids with sore throats and palatal petechiae has Strep.
I explain all of the above because I have many parents asking why we do not have an over the counter Strep test. The question then becomes would everyone who was found to have Strep on such a test need to be treated. Would not that make it easier on everyone? It turns out that many of the positive Strep tests would not need to be treated. Read on to find out why.
At any one time, many people carry a few Strep bacteria in the back of their throat. Depending on the person and the time of year, it can be as high as 10-20%. So if you stood out in front of the library and swabbed every child that entered the library (that would not be popular at all!!) on one day, tested all those swabs for Strep, and then called the families who were positive for Strep in 4-6 weeks to see if anyone they knew had been diagnosed with Strep, the number would be really small. So, our worry would be that if there was an over the counter Strep test, it would turn out many of these folks would have positive Strep tests who in fact are carriers. And carriers are not routinely treated.
Those kids (and adults) carrying Strep in the back of their throats can become ill with a viral illness, have a sore throat from the virus, but they would show Strep on a throat swab because of being a carrier. So a positive Strep test for them would not necessarily need to be treated with antibiotics -- and we seeing someone in the office for an ill visit will often clarify all these issues. Are there still times when we in the office treat someone that may actually be a carrier that really "just" has a viral sore throat? Yes, but an over the counter Strep test would certainly confuse us on this point.
So ultimately, a test for Strep not done by the doctor or nurse practitioner who has examined them would prove to be not enough information to make a decision about treatment. Therefore, it will always be good practice to see those patients with a possible Strep throat.