Supervised anterior nasal (AN) self-sampling for COVID-19 infection was found to be comparable to professional nasopharyngeal (NP) sampling. These results were published in European Respiratory Journal As a research letter to the editor.
The World Health Organization (WHO) has approved two rapid diagnostic tests for the detection of antigens (Ag-RDTs) by NP swab for SARS-CoV-2. However, NP swab tests are often uncomfortable and should be performed by healthcare professionals who wear personal protective equipment.
Testing via AN swabs can self-administer and when combined with Ag-RDT technology, may allow rapid self-monitoring of COVID-19 to expand.
Volunteers (n = 289) underwent this prospective face-to-face study of a self-collected dual swab following oral instructions, a combined oral / nose swab, and a NP swab collected by healthcare personnel. The oral instructions for the self-wipe were to insert the swab horizontally into the nostril 2 to 3 cm and rotate it for 15 seconds on either side of the nostril wall.
Self-administered AN swabs and NP swabs were tested with Ag-RDT (standard Ag Q COVID-19 test), and the oral / nasal swab was evaluated by real-time polymerase chain reaction (RT-PCR). All groups took place from September 23 to October 14, 2020 at the Charite University Hospital in Germany.
The average age of the participants was 34.7 years, 42.9% were women, 19.0% had comorbidities, and 97.6% had symptoms consistent with COVID-19 for an average of 4.4 days.
A total of 13.5% of study participants tested positive for SARS-CoV-2 infection by NP. All but two positive individuals were also shown to be positive with Anorexia nervosa, and no patient had anorexia nervosa alone. This agreement complies with high positive percentage agreement (90.6%; 95% CI, 75.8-96.8), negative percentage agreement (99.2%; 95% CI, 97.2-99.8), and mutual reliability (AN: k, 0.98; NP: K, 1.0).
The two different tests were from a person with a low viral load (10 days after symptoms appeared) and an individual who gently wiped their nose (user error).
The overall Ag-RDT sensitivity was 74.4% (95% CI, 58.9-85.4) and specificity was 99.2% (95% CI, 97.1-99.8) compared to the RT-PCR results. Among those with a high viral load (> 7.0 records10 RNA SARS-CoV-2 / swab), sensitivity with AN sampling (95.7%; 95% CI, 79.0-99.8) and NP sampling (100%; 95% CI, 85.7-100) was higher.
This study was limited to the fact that NP smears were generally administered in a way that the manufacturer did not recommend; However, the healthcare staff found it difficult to administer each protocol.
The authors of the letter concluded that Ag-RDT-tested self-administered swabs may be a viable rapid assessment of SARS-CoV-2 that can be easily administered at home.
Lindner AK, Nikolai O, Koch P, et al. Face-to-face comparison of the SARS-CoV-2 Rapid Antigen Detection Test with a self-collected anterior nasal swab versus a pro-collected nasopharyngeal swab. Your Respire c. 2020; 57 (3). Doi: 10.1183 / 13993003.03961-2020