Evaluation of PCL rapid point of care antigen test for detection of SARS‐CoV‐2 in nasopharyngeal swabs

While nucleic acid amplification tests remain the gold-standard for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, immunological methods can also be used to detect viral antigens or specific antibodies.1-9 Several rapid diagnostic employing antigen detection (Ag-RDTs) are now commercially available. However, there remains limited evidence on utility Ag-RDTs disease 2019 (COVID-19) and surveillance, with significant variability reported respect their performance a lack external validation many available tests.10 Thus, we initiated our study evaluate an Ag-RDT, PCL COVID-19 Ag fluorescent immunoassay (FIA), in hospitalized patients suspect SARS-CoV-2 infection. The results this test were compared qualitative quantitative parallel reverse transcription polymerase chain reaction (RT-PCR) enzyme-linked immunosorbent assay (ELISA) examinations. Patients suspected between May September 2020 at primary care hospital Siedlce, Poland, enrolled prospective observational study. simultaneously sampled by nasopharyngeal swabs RT-PCR. Swabs collected four times days intervals from all but one patient, that was examined only three times. Blood samples serology testing taken two 6-day interval, together first last sample. antigenic assessment performed using Rapid FIA (PCL) as point accordance manufacturer's instructions. molecular within few hours after collection central laboratory Warsaw commercial RT-PCR kits (Liferiver, DiaplexQ, Vitassay). Serology anti-SARS-CoV-2 immunoglobulin M (IgM), G (IgG), A (IgA) ELISA (Euroimmun). This Declaration Helsinki under patient informed consent anonymization data. total 42 (21 male 21 female) median age 57.7 years (range, 21–78) included resulting 167 swabs. time onset symptoms sample 8.3 2–16). summary over course presented Figure 1. Among swabs, 95 (56.9%) positive, 26 (15.6%) inconclusive, 46 (27.5%) negative RT-PCR, while 25 (15.0%) positive Ag-RDT. overall percent agreement Ag-RDT 48.9%. Positive obtained 36 (85.7%) patients, 1 (2.4%) had inconclusive results, 4 (9.5%) mixed hospitalization. revealed 15 (35.7%) patients. In case, points. Using reference standard, specificity 83.3%. RT-PCR-positive 14 cases, sensitivity 38.9%. nine detected sample, samples, cases consecutive samples. No persistence result during cycle threshold (CT) values Orf1ab gene ranged 18.5 36.5 (mean 27.8). positivity observed no later than 10 symptom (Table S1). presence antibodies 41 out (97.6%) Anti-SARS-CoV-2 IgA (90.5%) IgG frequently observed, IgM 20 (47.6%) investigation, 38.9% 83.3%, 48.9% significantly lower announced manufacturer, who 100% (27/27) 97.8% (44/45). Nonetheless, depend several factors, such onset, specimen content, other preanalytical analytical considerations.2, 4, 10, 11 study, 92.9% CT 25, which demonstrated crucial more sensitive high loads therefore its may recent symptoms, when load is very high. Although robust simple performance, insufficient capabilities replace Similar conclusions about different RDTs have been others.3-5 despite relatively low clinical among Ag-RDTs, they helpful reducing number requiring burden laboratories, particularly rapidly increasing worldwide. particular limits applicability both community testing. presymptomatic asymptomatic symptomatic thus leading individuals,10 deemed acceptable, seemingly correlates reduced transmission potential persons.12 failed accurately raising substantial concerns utility. could lead missing potentially delays initiating self-quarantine procedures contract tracing pending repeat Further studies should larger, diverse cohorts. conclusion, detecting active infection Moreover, RT poor. These highlight need careful evaluation novel assays before implementation practice surveillance. authors thank members staff municipal Siedlce National Institute Public Health-National Hygiene technical assistance. sole responsibility design, data collection, analysis, interpretation, writing report. declare conflict interests. Data upon reasonable request authors. Please note: publisher not responsible content functionality any supporting information supplied Any queries (other content) directed corresponding author article.