Objective: To determine the factors associated with an optimal diagnostic approach to a child with pharyngitis, characterize office laboratory methods for throat swab culture and group A streptococcal rapid antigen testing, and assess the potential impact of the Clinical Laboratory Improvement Amendments (CLIA) of 1988 on the performance of these tests.
Design and setting: Mailed survey to all board-certified primary care pediatricians from seven western states with telephone follow-up for nonrespondents.
Outcome measures: Differences in practice characteristics and use of office laboratory tests for physicians who usually (> 80%) diagnose pharyngitis using a recommended approach vs those who follow this approach less often (< 50%); characteristics of physicians who indicate that they intend to discontinue office throat culture because of CLIA and those who will continue to perform this test also are compared.
Results: Responses from 531 pediatricians were analyzed. Forty-four percent diagnosed pharyngitis appropriately for more than 80% of patients, and 17% did so for fewer than 50%. Optimal diagnosis was significantly more common among physicians who cultured throat swabs in their office (relative risk, 1.40; 95% confidence interval, 1.19 to 1.66) and less common among solo practitioners (relative risk, 0.71; 95% confidence interval, 0.56 to 0.88). Factors that may decrease the sensitivity of office throat culture include short duration of incubation (59%), lack of quality control (51%), and limited education of the persons reading results (6%). With implementation of CLIA, 24% of pediatricians reported that they already have discontinued or will discontinue office throat culture, and 23% have discontinued or will discontinue antigen detection testing for group A streptococci. Those most likely to stop office culture include solo practitioners and practitioners who do not currently perform quality control of culture methods.
Conclusions: Office culture for group A streptococci is strongly associated with an optimal diagnostic approach. Implementation of CLIA regulations may substantially decrease the number of physicians who perform this test. The balance between potential improvements in the quality of office culture with CLIA implementation and the decreased availability of this test needs to be assessed.