#246 Just wait a minute: Point-of-care testing for Group A Streptococcal pharyngitis
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- Sensitivity consistently ~85%, specificity consistently ~95%.1-3
- Positive likelihood ratio (LR+) 16.8, Negative likelihood ratio (LR-) 0.16.
- 1 systematic review, 6 studies (1937 patients):3
- Sensitivity=92%, specificity=99%.
- LR+ 92, LR- 0.08.
- Evidence published after above reviews:4-6
- Sensitivity=89-100%, specificity=91-100%.
- No significant difference in point-of-care performance between adult and pediatric populations.1-3
- Limitations: included studies had high heterogeneity, rapid testing not currently funded publicly.
- LR+ above 10 indicates test is a good help at ruling-in diagnosis.
- Clinical decision rules (i.e. CENTOR) have limited predictive value for diagnosing GABHS pharyngitis:7
- Meta-analysis (11 studies):7 Sensitivity=49% specificity=82%, LR+ 2.68.
- Empiric treatment for sore throat is common (~60%).8 Point-of-care testing may improve appropriate antibiotic prescribing.9
- Antibiotics for GABHS significantly reduces:10
- Sore throat at day three: 44% versus 71%, number needed to treat (NNT)=4.
- Peritonsillar abscess 0.1% versus 2%, NNT=47.
- Rheumatic fever 0.6% versus 1.7%, NNT=90.
- (rheumatic fever data from pre-1950, incidence has declined significantly in developed countries).
- Populations with higher incidence of GABHS complications, such as Canada’s Indigenous population, are more likely to benefit from antibiotic treatment.11-13
- Many international guidelines consider GABHS pharyngitis self-limiting and do not recommend antibiotic treatment.14
- Delayed antibiotic prescriptions decrease antibiotic utilization with no significant impact on symptom duration, or clinical outcomes, in GABHS pharyngitis.15