Performance of UMELISA SARS-CoV-2 antigen and STANDARD F COVID-19 in the diagnosis of COVID-19 in Villa Clara, Cuba

A cross-sectional descriptive study was carried out with the objective of describing the performance of UMELISA SARS-CoV-2 Antigen and STANDARD F COVID-19 Ag FIA in the diagnosis of COVID-19, at the Provincial Laboratory of Microbiology and Sanitary Chemistry of Villa Clara, during the month of February 2022. 1056 patients who underwent Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) using the QIAcube HT genome extraction technique, UMELISA SARS-CoV-2 Antigen and STANDARD F COVID-19 Ag FIA were included. Sensitivity, specificity, positive and negative predictive value were calculated as efficacy indicators and Spearman's Rho coefficient for the correlation between variables. The result was that 29.3% were sick, of which 189 were female, with a median age of 46 years. 74.8% had symptoms, most often fever, cough and runny nose. UMELISA SARS-CoV-2 Antigen showed higher specificity with 97.45%; while STANDARD F COVID-19 Ag FIA had higher sensitivity with 99.35%. It was shown that there is a significant inverse correlation between the RT-PCR cycle threshold and the fluorescence values ​​of both techniques studied (p=0.000). About a third of the patients studied were sick with symptoms, with a predominance of females. UMELISA SARS-CoV-2 Antigen turned out to be more useful in confirming the presence of the disease, while STANDARD F COVID-19 Ag FIA showed better performance in ruling out the presence of the disease.