Evaluating laboratory parameters for diagnostic accuracy in COVID-19 patients in a tertiary care Government Hospital in Greater Noida, UP, India

Abstract

Introduction: The occurrence, development, mechanism of prognosis and immune status of patients with COVID-19 are still unclear. Timely identification of virus carriers is vital not only to prevent their spread but also to more efficiently control disease progression. Objective: In this study, we have assessed the hematological characteristics of the patients. This study aimed to evaluate the accuracy of laboratory parameters in predicting cases with positive RT-PCR for COVID-19. Material and Methods: This was a cross sectional study that included 67 RTPCR +ve and 69 RTPCR -ve cases over a period of 5 weeks. The blood samples were collected from symptomatic patients presented to the cough OPD of the hospital and undergoing RT-PCR testing for Covid-19 between 9am to 4 pm on consecutive working days till the sample size requirement was met. On the day of swab sampling, blood sampling was done for each participant included in our study as mentioned in the sampling method above. All tests were performed in an appropriate autoanalyser after complying internal quality control. Results: The mean age of patients included in this study was 34.1 (24.05) years. The mean CT value among RTPCR positive patients was 22.7 (SD 4.99) with mean(SD) values of PCT, ferritin, D-dimer, LDH and CRP was 1.30 (SD 2.52), 197.2 (SD 284.40), 1.7 (SD 2.08), 353.5 (SD 186.43) 20.5 (SD 37.58) respectively . On the other hand the mean(SD) value of PCT, ferritin, D-dimer, LDH and CRP was 0.045 (SD 0.073), 84.6 (SD 137.51), 1.1 (SD 1.70), 328.5 (SD 99.84) and 5.7 (SD 16.67) respectively in the RTPCR negative patients. The sensitivity and specificity for procalcitonin analysis among these patients were 97% with CI (93.8-100) followed by serum ferritin with 82%, CI (70-94) and CRP levels were having just 77.3%, CI (61.2-93.4). Conclusion: In the current study, the AUC of procalcitonin and serum ferritin were above 0.80; thus, they are effective markers and have very good predictive value for predicting COVID-19. The mean values in the RTPCR positive patients were significantly high for the biochemical markers namely procalcitonin, ferritin and CRP whereas the mean levels of total protein and albumin were significantly lower among RTPCR positive patients compared to RTPCR negative patients. It seems that these blood laboratory parameters could be used in screening cases with positive RT-PCR for COVID-19. However, serum LDH, D Dimer, and vitamin D3 levels or liver function tests, renal function tests remain insignificantly linked with covid-19 positivity rate in this study.