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 32 RTPCR +ve and 64 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 for RT-PCR negative patients 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: Units The mean age of patients included in this study was 33 years. The frequency of male versus female patients included in this study was 60:40 while percentage ratio of them got infected were 28% and 21% respectively. The mean CT value of RT-PCR test was found to be 22.7. while mean PCT value was merely 0.3. The mean ferritin value came out to be 133.5 and mean D-dimer values calculated to be just 1.3. The mean LDH and CRP levels were 340.4 and 12.6 respectively. 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. 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 D levels or liver function tests, renal function tests remain insignificantly linked with covid-19 positivity rate in this study.