Background: The sputum saccharide chain antigen (Krebs von den Lungen-6 [KL-6]) is a serum biomarker of lung injury. We aimed to evaluate the clinical performance of the automated immunoassay analyzer HISCL-5000 in detecting KL-6 by comparing it with LUMIPULSE G1200 and determine the diagnostic value of KL-6 in interstitial lung disease (ILD).
Methods: A total of 145 serum samples from patients were tested using the two automated immunoassay analyzers in parallel.
Results: With a cutoff level of 500 U/mL, comparing the two systems, the agreement, sensitivity, specificity, and kappa value were 99.20%, 100%, 98.63%, and 0.984 (95% CI, 0.952-1.000), respectively. Spearman's correlation and ICC showed that there was a strong correlation between serum KL-6 levels measured by the two systems (rS = .991 [95% CI, 0.981-0.995], ICC = 0.984 [95% CI, 0.978-0.989], P < .01). The clinical diagnosis agreement rate in both systems was >80%. The kappa value was 0.707 (95% CI, 0.582-0.832; SYSTEM B) and 0.707 (95% CI, 0.588-0.826; SYSTEM A). The KL-6 level in the ILD group (1339.5, 662.5-2363) was significantly higher than that in the non-ILD groups (252, 158.5-353; Mann-Whitney U = 381.5, P < .01), and the KL-6 level (1558, 726-2772.5) in the ILD group detected by SYSTEM A was significantly higher than that in the lung cancer group (339, 207-424), other respiratory disease group (249, 194-366), and control group (198, 131.5-297; Kruskal-Wallis H = 63.19, P < .01).
Conclusions: HISCL-5000 showed well-concordant results with those of HISCL-5000 in the KL-6 tests. In patients with ILD, KL-6 showed a good diagnostic performance.
Keywords: HISCL-5000; KL-6; LUMIPULSE G1200; agreement; comparison; interstitial lung disease.
© 2019 The Authors. Journal of Clinical Laboratory Analysis Published by Wiley Periodicals, Inc.