Evaluating a Novel Nasal Sampling Method for SARS-CoV-2 Detection

Although the COVID-19 pandemic has entered an endemic phase, the disease continues to pose threats to public health. Some patients with underlying conditions remain at risk of hospitalization and severe illness, making convenient testing crucial for controlling viral spread.

Drawbacks of Current Nasopharyngeal Sampling?

The widely used nasopharyngeal swab sampling, while the "gold standard" for diagnosing SARS-CoV-2 infection, has some limitations. It requires trained healthcare workers to perform and is often uncomfortable or painful for patients. Thus, there is a need for a more convenient and non-invasive sampling approach to facilitate testing uptake.

The Novel Anterior Nasal Sampling Method

Recently, a new anterior nasal sampling (ANS) method has emerged, utilizing the Rhinoswab – a double-looped nylon-flocked swab designed to simultaneously collect samples from both nostrils. The swab is inserted and left in place for 60 seconds to maximize viral collection.

Evaluating Diagnostic Performance

This study aimed to assess the diagnostic performance of the ANS method. 412 suspected COVID-19 patients presenting to the emergency department underwent both ANS and standard nasopharyngeal sampling. Results showed that ANS detected 80.7% of positive cases, a significantly lower sensitivity compared to nasopharyngeal sampling.

Viral Load and Detection Rate

Further analysis revealed that for patients with high viral loads (Ct value <20), the ANS detection rate reached 95.8%. This suggests that the ANS sensitivity is closely tied to the viral load in the sample, performing better during early infection when viral loads are higher.

Advantages of the New Sampling Method

Despite slightly lower sensitivity than the standard method, ANS offers unique advantages. Healthcare workers generally found ANS easy to perform, with good patient tolerability. Most surveyed professionals preferred ANS sampling. With further validation, ANS could facilitate self-sampling in community settings, greatly increasing testing accessibility.

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References

Evaluation of a New Standardized Nasal Sampling Method for Detection of SARS-CoV-2 RNA via RT-PCR