What is the role of rapid antigen detection tests in the diagnosis of streptococcal pharyngitis?

Rapid antigen detection tests (RADTs) play a supportive role in the diagnosis of streptococcal pharyngitis by providing a quick and specific method to detect group A streptococcus (GAS) directly from throat swabs. They are particularly useful in primary care settings to aid clinical decision-making when the diagnosis is uncertain based on symptoms alone ¹.

According to UK guidelines, RADTs can help confirm GAS infection in patients presenting with sore throat symptoms suggestive of streptococcal pharyngitis, thereby guiding appropriate antibiotic prescribing and reducing unnecessary antibiotic use ¹.

From the literature, RADTs have demonstrated good specificity and reasonable sensitivity for detecting GAS, making them reliable for ruling in infection when positive (Leung et al., 2006; Cohen et al., 2016). However, sensitivity can vary, and a negative RADT does not completely exclude GAS, especially in children, where clinical judgment remains important (Cohen et al., 2016).

Recent studies in primary care have shown good agreement between RADTs and throat culture results, supporting their use as a rapid diagnostic tool in routine practice (Rystedt et al., 2023). This aligns with the guideline emphasis on balancing rapid diagnosis with clinical assessment to optimize management.

In summary, RADTs serve as a valuable adjunct to clinical evaluation in diagnosing streptococcal pharyngitis, enabling timely and targeted antibiotic treatment while helping to limit overprescribing.