The utility of rapid antigen detection testing for the diagnosis of streptococcal pharyngitis in low-resource
Anne W Rimoin1, Christa L Fischer Walker, Hala S Hamza
1Department of Epidemiology, UCLA School of Public Health, 650 Charles E. Young Drive S, CHS 41-275, Los Angeles, CA 90095, USA. arimoin@ucla.edu
Insights
Rapid antigen detection tests (RADTs) are a useful tool for diagnosing group A streptococcal (GAS) pharyngitis in pediatric clinics, especially where lab tests are unavailable. These tests offer timely results for effective treatment.
Area of Science:
- Pediatric Infectious Diseases
- Diagnostic Microbiology
- Public Health
Background:
- Group A streptococcal (GAS) pharyngitis is a common pediatric illness.
- Accurate and timely diagnosis is crucial for effective treatment and preventing complications.
- Access to reliable microbiological diagnosis varies globally, particularly in resource-limited settings.
Purpose of the Study:
- To assess the diagnostic utility of rapid antigen detection testing (RADT) for group A streptococcal (GAS) pharyngitis.
- To evaluate RADT performance in pediatric outpatient clinics across diverse international settings.
- To compare RADT results with throat culture as the gold standard.
Main Methods:
- Prospective evaluation of a commercial RADT in children aged 2-12 years presenting with pharyngitis symptoms.
- Study conducted in urban outpatient clinics in Brazil, Egypt, Croatia, and Latvia.
- Performance metrics including sensitivity, specificity, and predictive values were calculated and compared to culture results.
Main Results:
- Two thousand four hundred seventy-two children were enrolled across four countries.
- GAS prevalence by culture ranged from 24.5% to 39.4%.
- RADT demonstrated good performance compared to culture, with sensitivity ranging from 72.4% to 91.8% and specificity from 85.7% to 96.4%.
Conclusions:
- RADTs are a viable diagnostic option for GAS pharyngitis in pediatric settings.
- The tests provide timely results, which is advantageous in limited-resource regions.
- RADTs can be performed in-clinic, improving diagnostic accessibility where laboratory services are impractical.
Objectives:
To evaluate the utility of rapid antigen detection testing (RADT) for the diagnosis of group A streptococcal (GAS) pharyngitis in pediatric outpatient clinics in four countries with varied socio-economic and geographic profiles.
Methods:
We prospectively evaluated the utility of a commercial RADT in children aged 2-12 years presenting with symptoms of pharyngitis to urban outpatient clinics in Brazil, Croatia, Egypt, and Latvia between August 2001 and December 2005. We compared the performance of the RADT to culture using diagnostic and agreement statistics, including sensitivity, specificity, and positive and negative predictive values. The Centor scores for GAS diagnosis were used to assess the potential effect of spectrum bias on RADT results.
Results:
Two thousand four hundred and seventy-two children were enrolled at four sites. The prevalence of GAS by throat culture varied by country (range 24.5-39.4%) and by RADT (range 23.9-41.8%). Compared to culture, RADT sensitivity ranged from 72.4% to 91.8% and specificity ranged from 85.7% to 96.4%. The positive predictive value ranged from 67.9% to 88.6% and negative predictive value ranged from 88.1% to 95.7%.
Conclusions:
In limited-resource regions where microbiological diagnosis is not feasible or practical, RADTs should be considered an option that can be performed in a clinic and provide timely results.
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