Evaluation of a rapid method for diagnosing streptococcal pharyngitis in a rural community clinic.

Group A beta-hemolytic streptococcal pharyngitis is a common ailment whose accurate diagnosis is dependent on laboratory testing. Transport problems common to rural practices, for laboratory testing, could be resolved by a reliable rapid test. Laboratory evaluations of rapid streptococcal tests, performed mostly in research settings, indicate that the tests have acceptable specificity and sensitivity. This paper describes a comparison study of 248 consecutive throat swab specimens using a commercially available agglutination test with routine throat culturing. All agglutination testing was done by the office staff under actual working conditions, in a rural primary care clinic. The cultures were processed in the main regional microbiology laboratory. As a result of transportation delay, swabs were plated either within 6 h from collection or after 6 h. The test sensitivity (72%) and specificity (88%) compared well with that reported in the literature from microbiology laboratories, especially for swabs plated within six hours (80% and 93% respectively). The rapid test is an acceptable alternative to the standard culture technique in the family practice office under normal working conditions, provided that patients with negative results follow up with throat cultures.