Should a patient with symptoms of sore throat, cough, and chest tightness, and no known underlying medical conditions, be tested for COVID-19 (Coronavirus Disease 2019), influenza, and streptococcal pharyngitis?

Testing for COVID-19, Influenza, and Streptococcal Pharyngitis

Yes, this patient should be tested for COVID-19, and streptococcal pharyngitis testing should be strongly considered, while influenza testing depends on local seasonal activity and community prevalence. 1

COVID-19 Testing

The Infectious Diseases Society of America strongly recommends SARS-CoV-2 nucleic acid amplification testing (NAAT) in symptomatic individuals suspected of having COVID-19. 1 This patient meets testing criteria with sore throat, cough, and chest tightness—all recognized COVID-19 symptoms. 1, 2

• The pooled sensitivity of NAAT testing is 97% (95% CI, 93-99%) with 100% specificity, making it highly reliable for diagnosis. 1
• Testing should be performed regardless of vaccination status or prior infection history. 1
• A positive result directly informs therapeutic decisions, isolation requirements, and contact tracing. 1
• Testing is recommended based on community transmission levels, and during periods of community transmission, all symptomatic patients warrant testing. 1

Specimen Collection Options

Multiple specimen types are acceptable for COVID-19 testing: 1

• Nasopharyngeal (NP) swabs remain the reference standard
• Anterior nasal (AN) swabs show 81% sensitivity compared to NP
• Mid-turbinate (MT) swabs demonstrate 92% sensitivity
• Saliva specimens achieve 92% sensitivity overall
• All specimen types maintain 98-100% specificity 1

Streptococcal Pharyngitis Testing

Streptococcal pharyngitis testing is strongly indicated in this patient presenting with sore throat, as Group A Streptococcus requires specific antibiotic treatment to prevent serious complications. 3

• Sore throat is present in 30% of COVID-19 patients, but bacterial co-infection can occur. 2, 4
• Co-infection with COVID-19 and Group A Streptococcus has been documented and can be missed if testing focuses solely on COVID-19. 4, 5
• Throat culture remains the gold standard, though rapid antigen detection tests provide results within minutes. 3
• Untreated streptococcal pharyngitis can lead to acute rheumatic fever and post-streptococcal glomerulonephritis. 3

Clinical Context for Strep Testing

The modified Centor score helps assess streptococcal pharyngitis probability, but during the COVID-19 pandemic, relying solely on clinical scoring without testing risks missing bacterial co-infection. 5, 3

Influenza Testing

Influenza testing should be performed if there is active community transmission or during influenza season, as viral respiratory panels can detect multiple pathogens simultaneously. 1

• Differential diagnosis must include influenza virus, parainfluenza virus, adenovirus, respiratory syncytial virus, and metapneumovirus—all presenting with similar symptoms. 1
• Viral respiratory NAAT panels should ideally be rapidly performed with results used to direct appropriate antimicrobial use. 1
• Testing becomes particularly important when antiviral treatment for influenza would be indicated (within 48 hours of symptom onset). 1

Critical Testing Strategy

The sequential testing approach (testing for common pathogens first, then COVID-19 only if negative) has proven problematic and delays appropriate diagnosis and isolation. 5

• Early pandemic testing strategies that screened for other respiratory pathogens before COVID-19 resulted in diagnostic delays and inappropriate infection control measures. 5
• Simultaneous testing for COVID-19 and other respiratory pathogens is preferred to avoid delays in diagnosis and implementation of appropriate precautions. 5

Common Pitfalls to Avoid

Do not assume a single pathogen based on symptom presentation alone—co-infections occur and require different management strategies. 4, 5

• Sore throat, cough, and chest tightness overlap significantly between COVID-19, influenza, and streptococcal pharyngitis. 2, 6
• Gastrointestinal or upper respiratory symptoms may be the only initial manifestation of COVID-19 in some patients, preceding typical respiratory symptoms. 1, 7
• The absence of fever does not rule out any of these infections, though fever is present in 88.3% of COVID-19 cases. 2
• False-negative COVID-19 tests can occur (3% false-negative rate), so clinical suspicion should guide isolation and repeat testing if initial results are negative but suspicion remains high. 1

Practical Testing Algorithm

1. Obtain nasopharyngeal or anterior nasal swab for COVID-19 NAAT immediately 1
2. Perform throat swab for rapid streptococcal antigen test or culture 3
3. Consider viral respiratory panel if available and influenza is circulating in the community 1
4. Do not delay testing or wait for one result before ordering another—simultaneous testing prevents diagnostic delays 5
5. Implement appropriate isolation precautions immediately while awaiting results, treating the patient as potentially COVID-19 positive 1