De ritis ratio and neutrophil-to-lymphocyte ratio in the diagnosis of COVID-19

ABSTRACT

Aim: The outbreak of the novel coronavirus disease (COVID-19) has been affecting the world day by day. The definitive diagnosis of COVID-19 is made using the real-time polymerase chain reaction (RT-PCR) method. Although the RT-PCR method is the gold standard for confirming infection, it requires a specialized laboratory, expensive equipment, and trained personnel. Thus, simple and alternative laboratory tests are needed to predict PCR positivity and disease. Material and Methods: We analyzed laboratory parameters of 147 patients who were hospitalized with a pre-diagnosis of COVID-19 and sent RT-PCR samples. Of these, 76 tests were positive and 71 were negative. In addition to routine laboratory parameters, we also examined ratios derived from them, such as the De Ritis ratio (AST to ALT ratio) and Neutrophil-to-Lymphocyte Ratio (NLR). We investigated whether these parameters can predict the positivity or negativity of the PCR test. Results: CRP, D-dimer, Ferritin, AST values, NLR, and De Ritis ratio were found to be significantly higher in the PCR-positive group. It was observed that the lymphocyte count was lower in the positive group. Discussion: Our results suggest that routine laboratory tests that can be performed easily may also have the potential to predict COVID-19 positivity and negativity. These parameters can especially be used as an alternative in areas with a shortage of laboratories, equipment and personnel for PCR testing. Combining some hematological parameters and specific ratios derived from hematological parameters can help in identifying false positive/negative RT-PCR tests.