Nasopharyngeal Panbio COVID-19 Antigen Performed at Point-of-Care Has a High Sensitivity in Symptomatic and Asymptomatic Patients With Higher Risk for Transmission and Older Age

Abstract

Background Performance of point-of-care tests in different clinical scenarios and on different samples remains undetermined. We comprehensively evaluated the performance of the nasopharyngeal Panbio COVID-19 antigen Rapid-Test-Device. Method Prospective study including consecutive patients attending three primary care centers (PCC) and an emergency department. The antigen test was performed at point-of-care in nasopharyngeal and nasal swabs, and in saliva. Positive and negative percent agreement (PPA, NPA) were calculated with the RT-PCR assay as reference standard. Results Of 913 patients included, 296 (32.3%) were asymptomatic and 690 (75.6%) came from the PCC. Nasopharyngeal swabs were collected from 913, nasal swabs from 659, and saliva from 611 patients. RT-PCR was positive in 196 (21.5%) nasopharyngeal samples (NPS). Overall PPA (95% CI) in NPS was 60.5% (53.3-67.4), and it was lower in nasal swabs (44.7%) and saliva (23.1%). Test performance in NPS was largely dependent on the cycle threshold (Ct) in RT-PCR, with PPA of 94% for Ct≤25 and 80% for Ct<30. In symptomatic patients, the PPA was 95% for Ct≤25; 85% for Ct<30, and 89% for the symptom triad of fever, cough and malaise. Performance was also dependent on age, with PPA of 100% in symptomatic patients >50 years with Ct<25. In asymptomatic patients, the PPA was 86% for Ct<25. In all cases, NPA was 100%. Conclusion The nasopharyngeal Panbio COVID-19 antigen test performed at point-of-care has a good sensitivity in symptomatic patients with Ct<30 and older age. The test was useful to identify asymptomatic patients with lower Ct values.

Diverse high-affinity DNA aptamers for wild-type and B.1.1.7 SARS-CoV-2 spike proteins from a pre-structured DNA library

“…For NP sampling, the sensitivity and specificity were found to be 86.1% and 99.9%, respectively; however, throat sensitivity and saliva sensitivity were found to be only 57.7% and 2.6%, respectively ( 6 ). Even when using lower nasal swabs, the PanBio™ test still requires supervised self-swabbing for sample collection, and even then shows lower sensitivity than is obtained for nasal pharyngeal swab samples ( 7 ), highlighting the need for improved rapid tests with better clinical performance.…”

Diagnostic Accuracy of SARS-CoV-2 Rapid Antigen Detection Testing in Symptomatic and Asymptomatic Children in the Clinical Setting

“…Several antigen-based rapid diagnostic tests (RDTs) have been marketed to fill this gap. Among them, the Panbio-COVID-19 Ag Rapid Test Device (referred to here as P-RDT) has displayed an overall sensitivity ranging between 61% and 92% ( 2 – 7 ) in adults compared to nasopharyngeal RT-PCR. Sensitivity was improved for higher viral loads (VLs), shorter duration of symptoms and/or in symptomatic patients ( 2 – 6 ).…”

Development and Evaluation of a new Swiss Made SARS-CoV-2 antigen-detecting rapid test

“…The analytical sensitivity based on RT-PCR CT value, was also extrapolated using the 20 positive samples (figure 1) and was defined at a CT value of 31.5. The TPP from WHO defined an analytical sensitivity of at least 30 cycle threshold (CT) values [10]. A Point-of-Care (POC) test that can consistently detects the most infectious patients, with high viral load of at least 10 6 genomic copies/ml, in order to interrupt transmission.…”

“…It has been noted that the sensitivity increases with high viral load (RT-PCR Cycle threshold < 30). The World Health Organization (WHO) published a target product profile with the minimal and desirable analytical and clinical performances (TPP WHO) [10].…”

“…A patient with a positive Ag-RDT result within 5 days after symptom onset can be considered to have a SARS-CoV-2 infection, because these individuals are more likely to have high viral loads [11]. However, a negative result must be interpreted with caution due to reduced sensitivity with low viral load and a confirmation test (RT-PCR) is recommended [10].…”