Original Article

Sensitivity for Diagnosing Group A Streptococcal Pharyngitis from Manufacturers is 10% Higher than Reported in Peer-Reviewed Publications

Authors: Raj Vachhani,BS, Toral Patel, MD, Robert M. Centor, MD, Carlos A. Estrada, MD, MS

Abstract

Objectives: Meta-analyses based on peer-reviewed publications report a sensitivity of approximately 85% for rapid antigen streptococcus tests to diagnose group A streptococcal (GAS) pharyngitis. Because these meta-analyses excluded package inserts, we examined the test characteristics of rapid antigen streptococcal tests and molecular methods that manufacturers report in their package inserts.

Methods: We included tests available in the US market (Food and Drug Administration, period searched 1993–2015) and used package insert data to calculate pooled sensitivity and specificity. To examine quality, we used the Quality Assessment of Diagnostic Accuracy Studies-2. We excluded 26 tests having different trade names but identical methods and data.

Results: The study design was prospective in 41.7% (10 of 24). The pooled sensitivity of the most commonly used method, lateral flow/ immunochromatographic, was 95% (95% confidence interval [CI] 94–96) and the pooled specificity was 98% (96–98); 7108 patients. The pooled sensitivity of the polymerase chain reaction or molecular methods was 98% (95% CI 96–98) and the pooled specificity was 96% (95% CI 95–97); 5685 patients.

Conclusions: Package inserts include sponsored studies that overestimate the sensitivity of rapid tests to diagnose GAS pharyngitis by approximately 10%. Physicians should understand that package inserts overestimate diagnostic test utility; a negative test cannot be used to exclude GAS pharyngitis.

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