From the Guidelines
Over-the-counter tests for flu and COVID-19 generally cannot detect H3N1 specifically, and if you suspect you have H3N1 influenza, you should consult a healthcare provider who can order laboratory-based diagnostic tests that can identify specific influenza subtypes. Most OTC flu tests are designed to detect influenza A and B viruses broadly, without distinguishing between specific subtypes like H3N1. Similarly, COVID-19 home tests are specifically designed to detect SARS-CoV-2, not influenza viruses.
The design limitations of these tests, as noted in studies such as 1 and 1, mean they typically use antibodies that bind to general proteins found across influenza viruses rather than subtype-specific markers. This is why they cannot specifically identify any influenza A virus subtypes, including H3N1.
Some key points to consider:
- The sensitivity and specificity of rapid influenza diagnostic tests (RIDTs) can vary, but they generally have high specificity (>90%) and low to moderate sensitivity (20%–70%) compared to other influenza tests 1.
- Negative RIDT results should not be used to make treatment or infection-control decisions, especially when influenza viruses are known to be circulating in the community 1.
- More sensitive and specific tests, such as viral culture or RT-PCR, are needed for a definitive diagnosis and can provide specific information regarding the antigenic characteristics of influenza viruses, data on antiviral resistance, and influenza A virus subtype 1.
- Early detection is crucial because antiviral medications like oseltamivir (Tamiflu) are most effective when started within 48 hours of symptom onset, as recommended in guidelines such as those from the American Academy of Pediatrics 1.
Given the importance of early and accurate diagnosis for effective treatment and management of influenza, consulting a healthcare provider for laboratory-based diagnostic tests is the best course of action if H3N1 influenza is suspected.
From the Research
Over-the-Counter Tests for Flu and Covid
- The provided studies do not directly address the question of whether over-the-counter tests for flu and Covid can detect H3N1 2, 3, 4, 5, 6.
- However, the studies discuss the treatment and prevention of influenza A and B, including the use of antiviral agents such as oseltamivir and zanamivir 2, 3, 4, 5, 6.
- The studies also mention the importance of early initiation of antiviral treatment, preferably within 48 hours of symptom onset, to produce favorable outcomes in patients with influenza infection 3.
- Additionally, the studies highlight the need for alternative treatment strategies with available influenza antivirals to combat drug-resistant influenza viruses 5.
Detection of H3N1
- There is no direct evidence in the provided studies to suggest that over-the-counter tests for flu and Covid can detect H3N1 2, 3, 4, 5, 6.
- However, the studies do discuss the epidemiological features of influenza cases, including the subtypes A(H1N1), A(H3N2), and B 2.
- The studies also mention the use of neuraminidase inhibitors, such as oseltamivir and zanamivir, which are effective against influenza A and B, including H3N2 4, 5, 6.
- But, there is no specific information on the detection of H3N1 using over-the-counter tests for flu and Covid 2, 3, 4, 5, 6.