Do You Need to Do Both Strep Test and COVID-19 Test?
Yes, when a patient presents with sore throat and fever, you should perform both a Group A Streptococcus test and a COVID-19 test, as these infections can co-occur and require different management strategies.
Clinical Reasoning
The symptoms of streptococcal pharyngitis and COVID-19 overlap substantially—both can present with sore throat, fever, and systemic symptoms 1. Because clinical features alone cannot reliably differentiate between these conditions, and because each requires specific treatment decisions (antibiotics for strep, isolation protocols for COVID-19), testing for both pathogens is warranted 2, 3.
When to Test for Both
Test for both GAS and SARS-CoV-2 when:
- Patient presents with acute pharyngitis AND fever
- No clear viral features that exclude bacterial infection (absence of cough, rhinorrhea, conjunctivitis, hoarseness, or oral ulcers suggests possible strep) 1
- Patient is in the appropriate age range (5-15 years for strep, though adults can be affected) 3
- Clinical scoring suggests possible strep (Centor ≥3 or FeverPAIN ≥2) 4
Testing Approach
For Group A Streptococcus:
- Use rapid antigen detection test (RADT) as first-line 1, 5
- In children/adolescents: back up negative RADT with throat culture due to lower sensitivity 5, 3
- In adults: negative RADT alone is generally sufficient (lower disease incidence and rheumatic fever risk) 5, 3
For COVID-19:
- Use NAAT (nucleic acid amplification test) as the gold standard for symptomatic patients 2, 6
- Antigen testing is acceptable but negative results should be confirmed with NAAT if clinical suspicion remains high 2
- Collect nasopharyngeal, anterior nasal, or oropharyngeal swab specimens 6
Evidence for Co-infection
Co-infections with GAS and SARS-CoV-2 do occur 7, 8. A 2025 retrospective study found that 9.3% of patients tested for both had co-infections, with cases identified exclusively after July 2022 8. These co-infected patients typically presented with mild symptoms (fever and sore throat) but had distinctive laboratory findings 8. The study noted that limited testing may contribute to underdiagnosis of co-infections 8.
Important Caveats
Do NOT test for strep when:
- Strong viral features are present: cough, rhinorrhea, hoarseness, conjunctivitis, oral ulcers, or viral exanthem 1, 9
- Child is <3 years old (unless risk factors like infected sibling present) 3
- Clinical score is very low (Centor 0-1) 4
The key pitfall is singular focus: During the COVID-19 pandemic, physicians may have developed tunnel vision for COVID-19 testing while neglecting to screen for GAS 7. This is problematic because untreated strep pharyngitis can lead to acute rheumatic fever (especially in children) and suppurative complications 1, 3.
Clinical Impact
Testing for both conditions matters for morbidity and mortality:
- Strep: Untreated GAS pharyngitis can cause acute rheumatic fever (preventable if treated within 9 days), suppurative complications (peritonsillar abscess, cervical lymphadenitis), and ongoing transmission 3
- COVID-19: Requires isolation protocols, contact tracing, and consideration of antiviral therapy in high-risk patients 2
- Both: Appropriate antibiotic use only when indicated reduces antimicrobial resistance and adverse effects 3
The optimal approach uses both clinical scoring and laboratory confirmation to avoid overtreatment (antibiotics for viral pharyngitis) and undertreatment (missing bacterial infection) 10, 4.