Could tear be an alternative specimen for SARS-CoV-2 detection?

Abstract

Abstract Objectives For a definitive diagnosis of COVID-19, respiratory tract samples are evaluated by polymerase chain reaction (PCR). In our study, PCR using a tear sample was used to diagnose COVID-19, and it was questioned whether it was a screening method. Unlike the general practice, Schirmer strips were used instead of a swab for tear sample collection in this study. In addition, the diagnostic values of serum procalcitonin (PCT), C-reactive protein (CRP), and Neutrophil (NEU) count in predicting COVID-19 disease from tears were also questioned. Methods A total of 94 patients who were positive for COVID-19 by PCR test were included in this study. Tear samples were obtained from patients with Schirmer strips, commonly used in eye examination, and studied with the PCR technique. CRP, PCT value, and NEU count were also compared between the positive and negative groups of the PCR. The obtained data were analyzed using the R Studio software, and the results were considered statistically significant for p<0.05. Results Of these patients, 61 (64.9%) tear PCR was negative, and 33 (35.1%) tear PCR was positive. The mean age was 61.72 ± 17.62 years. The patients were divided into two groups: tear PCR positive and negative. There was no significant age difference between these groups. As a result of ROC Analysis; When serum PCT, CRP, and NEU % values were examined in predicting COVID-19 disease from tears, it was seen that CRP (p=0.027) and especially PCT (p=0.003) values of patients with PCR-positive were significantly higher. Conclusions PCR study on tears collected with Schirmer strips is a different and non-invasive method, but it was concluded that the proposed method could not be used as a screening test. In addition, significantly higher serum PCT values were found in patients with COVID-19 positivity in tears (p<0.05).