IDSA’s new GAS pharyngitis guidance emphasizes selective testing using clinical scoring to reduce overtreatment and antibiotic misuse.
The Infectious Diseases Society of America (IDSA) has released updated clinical practice guidelines for group A streptococcal (GAS) pharyngitis, published October 14, 2025, marking the first major revision since 2012. The new guidance emphasizes the use of validated clinical scoring systems to guide diagnostic testing and reduce unnecessary antibiotic use.
Shift in diagnostic approach
The 2025 update highlights the continued challenge of distinguishing viral from bacterial causes of sore throat, noting that most cases are viral and self-limiting. GAS remains the cause in up to 15% of adults and 30% of children, but overdiagnosis contributes to antibiotic overuse and resistance.
For the first time, IDSA formally recommends that clinicians use clinical scoring systems—such as Centor or McIsaac criteria—to assess the likelihood of GAS before performing diagnostic testing. The goal is to identify patients with a low probability of GAS infection, in whom further testing is unlikely to change management.
“The principal utility of a scoring system is to identify patients with low probability of GAS pharyngitis,” the panel stated, adding that doing so may reduce false-positive results, unnecessary testing, and antibiotic prescribing.
The guideline issues a conditional recommendation with very low certainty of evidence, reflecting the limited number of comparative studies, but notes that the balance of benefits and harms supports implementation.
Key updates from prior guidance
The 2012 IDSA guideline emphasized throat swab testing—via rapid antigen detection test and culture—as the diagnostic standard, given that clinical features alone could not reliably differentiate bacterial from viral causes.1,2
In contrast, the 2025 update recommends incorporating a pretest scoring system to guide who should be tested, representing a shift toward more selective and evidence-based testing.
Unchanged in the new guidance is that children younger than 3 years remain excluded from testing recommendations due to atypical presentation and low incidence.
Although the 2012 guideline focused heavily on antibiotic regimens, including penicillin or amoxicillin as first-line therapy, the 2025 update defers treatment discussions to future installments, with this first part focusing solely on diagnosis and testing strategy.
Supporting evidence and rationale
A systematic review identified 6 observational studies comparing scoring systems with clinician judgment alone. Findings from studies using Centor, McIsaac, and Breese criteria showed similar or slightly higher diagnostic accuracy compared with usual clinical practice.
The IDSA panel concluded that:
The new recommendation applies to both adults and children but not to those younger than 3 years or with atypical clinical presentations. The guideline also advises clinicians to consider individuals with high risk for testing regardless of score, such as patients with household GAS exposure, previous rheumatic fever, or symptoms suggesting systemic infection.
The IDSA notes that future updates will address testing modalities, treatment options, and posttreatment management.
References
