Although the number of new Covid-19 cases has peaked in parts of the nation, the omicron variant continues to surge in many states, leaving hospitals at capacity, schools once again pivoting to distance-learning and businesses struggling to keep workers on-site due to increasing infections. The explosion in cases since the new year has placed an enormous strain on testing sites, which has created a renewed interest in at-home testing options. As the omicron variant became common throughout the country, patients often experienced a sore throat during the early stage of the disease. This led to multiple claims on social media suggesting that a throat swab may lead to a more accurate result compared to the recommended nasal swab for at-home testing.
So should you swab your throat when performing an at-home test?
When testing for an infectious disease like Covid-19, details matter. One might assume there aren’t any significant differences between a throat and nasal swab that could negatively impact the performance of a test, but there is the potential for things to go awry. Rapid antigen tests, such as those used for Covid-19, are inherently susceptible to the pH level – or acidity – of the sample being tested. It turns out that the pH of the throat can be substantially lower compared to the nose, especially after eating or drinking. A low pH environment, such as one created by drinking coffee, fruit juice or soft drinks, can lead to a false-positive Covid-19 antigen result. This observation was keenly made by school-aged children in the United Kingdom, who used this limitation of Covid-19 antigen tests as a way to get out of class.
If Covid-19 has taught us anything, it’s that we need to be open to change, adapt our strategies as we learn, and never assume we have this virus figured out. While it is certainly possible for a new variant to emerge that is more prevalent in one part of the body compared to another (e.g., throat versus the nose), we need to continue to rely on science and data to inform our decision-making and testing strategy. If we make a change in how we diagnose this disease, it should be based on carefully designed studies that support a shift in our approach. The findings from a recent study (not yet peer-reviewed) of more than 700 people seeking testing at a community site in the San Francisco area underscored this point. This study compared rapid antigen testing of nasal and throat swabs to the gold-standard, PCR. The results showed that antigen testing of nasal swabs detected 85.7% of cases compared to only 46.9% when throat swabs were tested. While the results of this study support continued caution in the use of throat swabs for Covid-19 antigen testing, additional studies are needed to confirm these findings. Until then, let’s continue to follow the science, not the advice of social media influencers.
Read the full article on forbes.com.
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