strep throat

[Aaatrm]

My 17 year old daughter has kissing tonsils.  About 2 days ago she started with a sore throat, and then about a day later she started with a fever and an extremely sore throat.  Her normally large tonsils became swollen and they have white spots on them.  (She has had strep three times in the past two years.)  Her peds office had urgent care over the weekend and the doctor did a rapid strep test, which came back negative.   He said he was surprised, as he really assumed it would be positive.  He said he would send a culture out to the lab and we would have the results in 2-3 days.  However, we are due to go on vacation in 3 days.
I thought that I had heard somewhere that a rapid strep test could show negative if it's done too soon, meaning if it was less than 24 hours since the patient exhibited symptoms.  Would it make sense to have a second rapid strep test done (which my doctor is reluctant to do -- they said to wait for the lab results in three days)?  My concern is that she feels really lousy and cannot eat anything because her throat is so sore.  She's even having trouble drinking water.   By the time the lab results come back, she will have had symptoms for 5 days (Sat thru Wed).  

[Aaatrm]

Thanks so much.  
I called the office today and they want to wait for the culture result from the lab before starting her on an antibiotic.  They did suggest that I take her for blood work to test for mono too.

[Jeffrey S Guy, M.D., M. Sc.]

Often with a rapid strept, some will start on antibiotics for a few days until the culture returns from microbiology.  The rapid strep can sometimes be read as negative when the person really has strept throat (false positive test) in one third of the time in some research series.  Regardless of the results, your daught still feels terrible.  I would get her into to see her pediatrician.