Use of a high-sensitivity rapid strep test without culture confirmation of negative results: 2 years' experience

Abstract

Background: Optimal diagnostic management of patients with pharyngitis is controversial. In our study, we compared streptococcal complication rates at a large suburban medical center during 2 time periods: when pharyngitis patients were managed almost exclusively with throat culture and when they were managed primarily with a high-sensitivity antigen test without culture confirmation of negative results.

Methods: Using a combination of Current Procedural Terminology and International Classification of Diseases, Ninth Revision codes, we studied all patients seen for either pharyngitis or known streptococcal complications during a 4-year period. We then reviewed all available charts of patients with known streptococcal complications for coding accuracy. We compared streptococcal complication rates during each -time period.

Results: A total of 30,036 patients were seen for pharyngitis during the 4 years. A streptococcal diagnostic test was used in 66% of patient encounters. During the first 2 years (period 1), 99.9% of the tests ordered were blood agar plate throat cultures. During the second 2 years (period 2), 76.6% of tests ordered were high-sensitivity antigen tests without culture confirmation of negative results. Suppurative complications occurred in 37 patients in period 1 and 36 patients in period 2. There were no cases of acute rheumatic fever in either period. There was one case of poststreptococcal glomerulonephritis in period 2.

Conclusions: Use of a high-sensitivity antigen test without culture confirmation of all negative results has not been associated with an increase in suppurative and nonsuppurative complications of group A beta-hemolytic streptococci.