Performance evaluation of standard™ Q Covid-19 Ag saliva test in detection of Covid-19 among patients in tertiary hospital

ABSTRACT

@#Newer diagnostic tests for COVI D-19 such as antigen tests are being used for rapid identification of cases. Compared to reverse transcriptase polymerase chain reaction (RT-PCR), these tests offer simpler collection and processing. This study aims to determine the accuracy of a SARS-CoV-2 antigen-detecting rapid diagnostic test (Ag-ROT) using saliva compared to nasopharyngeal and oropharyngeal swab (NPS/OPS) RT- PCR among patients tested in the Emergency Room at Makati Medical Center. Patients who underwent NPS/OPS RT-PCR and who consented to participate in the study were asked to submit salivary sample to be analyzed using the Standard™ Q Covid-19 Ag Saliva Test kit. A total of 366 samples were collected . The overall accuracy was 81 .69% with a sensitivity of 63.58% and a specificity of 97.93%. Subgroup analyses as to processing time, number of days from symptom onset, and presence or absence of symptoms had no effect the overall accuracy. The Standard™ Q Covid-19 Ag Saliva Test kit was able to satisfy the ~97% specificity recommended by the WHO for SARS-CoV-2 Ag-RDTs but did not meet the minimum performance requirements of ~80% sensitivity. A positive test results can help in the initiation of early treatment and isolation of cases, but a negative test should still be confirmed by NPS/OPS RT-PCR test.