Laboratory testing is commonly performed in patients with COVID-19. Each of the laboratory parameters has potential value for risk stratification and prediction of COVID-19 outcomes. This systematic review and meta-analysis aimed to evaluate the difference between these parameters in severe and nonsevere disease and to provide the optimal cutoff value for predicting severe disease.

We performed a systematic literature search through electronic databases. The variables of interest were serum procalcitonin, albumin, C-reactive protein (CRP), D-dimer, and lactate dehydrogenase (LDH) levels in each group of severity outcomes from COVID-19.

There were a total of 4848 patients from 23 studies. Our meta-analysis suggest that patients with severe COVID-19 infections have higher procalcitonin, (mean difference 0.07; 95% CI 0.05–0.10; p < 0.00001), CRP (mean difference 36.88; 95% CI 29.10–44.65; p < 0.00001), D-Dimer (mean difference 0.43; 95% CI 0.31–0.56; p < 0.00001), and LDH (mean difference 102.79; 95% CI 79.10–126.49; p < 0.00001) but lower levels of albumin (mean difference −4.58; 95% CI −5.76 to −3.39; p < 0.00001) than those with nonsevere COVID-19 infections. The cutoff values for the parameters were 0.065 ng/mL for procalcitonin, 38.85 g/L for albumin, 33.55 mg/L for CRP, 0.635 μ/L for D-dimer, and 263.5 U/L for LDH, each with high sensitivity and specificity.

This meta-analysis suggests elevated procalcitonin, CRP, D-dimer, and LDH and decreased albumin can be used for predicting severe outcomes in COVID-19.