Comparison of the simultaneous conjunctiva and oropharynx–nasopharynx swab results in patients applying to the SARS-CoV-2 outpatient clinic for the first time

Abstract

The aim is to comparatively evaluate the results of simultaneous conjunctiva and oropharynx–nasopharynx (ONP) swabs in patients who had presented to the outpatient department with a suspicion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). An ONP sample was obtained following bilateral conjunctiva swabs in 85 subjects with a contact history or symptoms but unknown SARS-CoV-2 status and with no ocular symptoms or findings. The results were evaluated according to the patient's symptoms and how the swab was taken. The conjunctiva swab was positive in 29 (34.1%) cases and the ONP swab in 20 (23.5%) cases. Both methods produced positive results in 11 (14.1%) cases. The mean cycle threshold (Ct) value was 30.15 ± 3.41 in symptomatic cases and 33.62 ± 1.76 in asymptomatic cases (p =.008). The mean Ct value was 24.37 ± 3.48 when only the ONP swab was positive and 31.22 ± 1.99 when only the conjunctiva swab was positive. In cases that were positive by both methods, the mean Ct value was 25.21 ± 4.94 for the ONP swab and 30.29 ± 5.05 for the conjunctiva swab. We found higher SARS-CoV-2 detection rates with the conjunctiva swab than the ONP swab in cases with unknown SARS-CoV-2 status in the early period. In addition, the conjunctival viral load seemed to be higher in symptomatic cases than in asymptomatic cases. We, therefore, believe a conjunctiva swab could be an alternative method to detect SARS-CoV-2 at the time of the first presentation to the outpatient department. © 2021 Wiley Periodicals LLC