ABSTRACT
Background: Lung injury is common in coronavirus disease 2019 (COVID-19) patients. The severity of lung injury appears to be reflected in serum Krebs von den Lungen-6 (KL-6), a glycoprotein expressed on type II alveolar epithelium. This study aims to assess the role of serum KL-6 in reflecting the severity of lung injury in COVID-19 patients. Methods: A systematic search was conducted in Scopus, PubMed, Wiley Online Library, and ProQuest. Articles were screened based on several eligibility criteria and assessed for study quality using Newcastle-Ottawa Scale. Results: This systematic review included four studies involving a total of 151 adult COVID-19 patients. Pooled analysis revealed that serum KL-6 was significantly higher in severe patients (SMD = 1.16; 95% CI = 0.691.63) with moderately high pooled sensitivity (79%; 95% CI = 6191%) and specificity (86%; 95% CI = 7295%). Conclusion: High serum KL-6 may depict more severe lung injury in COVID-19 patients with moderately high sensitivity and specificity.