Abstract

Background: It is a fact that the ongoing worst ever pandemic caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), have affected millions of people with large number of casualties worldwide. There has been now several published studies regarding the clinical, laboratory and radiological findings of COVID 19 infections. The aim of this study was to combine the two common hematological abnormalities viz. lymphopenia and elevated LDH to increase the sensitivity of diagnosis of COVID-19 infection. We compared the LDH-to-lymphocyte ratio in patients with COVID-19 infection admitted in the ICU and general ward to assess its relation with severity of disease. Our study may help in early identification and categorization of COVID-19 patients.
Methodology : A total of 100 adult patients diagnosed by RT-PCR for COVID-19 were recruited for the study. One patient was excluded due to unclear history. We included 49 patients with severe disease from intensive care unit (ICU) and 50 patients from COVID ward with less severe disease. Serum lactate dehydrogenase (LDH) levels and absolute lymphocyte counts (ALC) of these patients were obtained during admission and the ratio of LDH to ALC was calculated for both groups. The collected data was statistically analyzed.
Results : Serum LDH levels were higher in ICU patients group compared to the COVID ward patients. ALC on admission were lower in ICU patients than the ward patients. In both cases the difference was statistically significant with p value of 0.001 in all the cases. A p value of <0.05 was considered as statistically significant. LDH/ALC ratio median of all included patients was 0.390 with interquartile range (IQR) 0.450. In COVID ICU group the median of the LDH/ALC ratio was 0.580 with IQR 0.340 and in COVID ward group median was 0.220 with IQR 0.240. It suggests that the LDH/ALC ratio is significantly higher (p value of 0.001 )  in COVID ICU patients with severe disease in comparison to COVID ward patients having non-severe disease.
Conclusion: LDH/ALC ratio on admission can be used as a sensitive prognostic marker in COVID-19 patients which can help in early identification of COVID patients who have potential risk to develop severe disease.