Evaluation of the throat culture as a follow-up for an initially negative enzyme immunosorbent assay rapid streptococcal antigen detection test

In a study of the efficacy of following up an initially negative enzyme immunosorbent assay (EIA) rapid streptococcal antigen detection test with a throat culture, 2 double swabs (4 total) were obtained from 264 pediatric patients with sore throats. Although a throat culture was more specific (97%) than the EIA (89%), the sensitivity (87%) and negative predictive value (97%) of a single EIA was the same as that of a single throat culture. A follow-up throat culture was more accurate than a follow-up EIA. We conclude that the office EIA tested results in more false positives but misses no more true positives than a single throat culture processed by a well-controlled microbiology laboratory. If a follow-up technique is used for an initially negative EIA rapid streptococcal antigen detection test, the throat culture is the superior test and would be equally applicable following an initially negative throat culture or EIA.