The role of laboratory parameters in predicting severity of COVID-19 disease in pregnant patients

We aimed to examine the relationship between laboratory markers and the severity of the disease in pregnant women diagnosed with coronavirus disease 2019 (COVID-19). Clinical records were retrospectively reviewed for 112 pregnant women. Patients diagnosed with COVID-19 were divided into two groups as mild/moderate and severe. The relationship between predicting the severity of the disease and laboratory parameters was investigated. Neutrophil lymphocyte ratio, C-reactive protein (CRP), ferritin and aspartate aminotransferase levels were significantly higher in severe COVID-19 cases than mild/moderate cases (p = .048, p = .003, p = .015 and p = .035, respectively). CRP was found to be the most useful marker in terms of diagnostic performance with a cut off value of 10.8 (sensitivity 80%, specificity 56.1%, NPV 88.5% and PPV 40.0%). The best diagnostic performance was obtained using CRP and ferritin combined with cut-offs of 10.8 mg/L for CRP and 26.5 mu g/L for ferritin. Combined CRP and ferritin showed sensitivity, specificity, negative predictive value and positive predictive value of 94.7%, 52.8%, 96.6% and 41.9%, respectively, in predicting severe COVID-19. The combination of CRP and ferritin parameters may be useful in estimating the severity of the disease in pregnant patients who were initially diagnosed with COVID-19. Impact Statement What is already known about this subject? Coronavirus disease 2019 (COVID-19) can rapidly develop into acute respiratory distress syndrome (ARDS) and result in serious complications in some pregnant patients. Therefore, timely diagnosis of patients is crucial. Most previous reports of COVID-19 laboratory results are based on data from the general population and limited information is available regarding pregnancy status. Although laboratory medicine makes an important contribution to clinical decision making in many infectious diseases, including COVID-19, studies to predict the severity of the disease with laboratory markers are limited and the results are contradictory. What do the results of this study add? Our study shows that C-reactive protein (CRP), neutrophil lymphocyte ratio (NLR), ferritin and aspartate aminotransferase (AST) are associated with severe disease in pregnant women diagnosed with COVID-19. In addition, the use of combined CRP and ferritin appears to have higher sensitivity and negative predictive value than using other tests alone. Furthermore, this study shows that coagulation markers are not useful in predicting disease severity in pregnancy. What are the implications of these findings for clinical practice and/or further research? Predicting the severity of COVID-19 disease in pregnancy can prevent unnecessary hospitalisations and allow the implementation of the necessary clinical approach. Further studies can focus on the clinical usefulness of these parameters in predicting severe COVID-19 in pregnancy.