[Establishment of reference intervals and cut-off value by an enzyme immunoassay for KL-6 antigen, a new marker for interstitial pneumonia].
KL-6 antigen is a novel marker for interstitial pneumonia. In a similar manner as the protocol developed in serum protein standardization project, reference intervals for KL-6 was established using a newly developed enzyme immunoassay. The cut-off value was thus determined by ROC curves. Reference interval for a total of 273 subjects was 94.9-458.2 U/ml (median , 181.1 U/ml), with the age-dependent elevation. Sex-difference was observed over 40 years of age, being higher in males than in females (p < 0.01). Although no statistical difference, smokers showed higher levels than non-smokers did. The KL-6 value was 133.0-527.0 U/ml in 23 cases with diseased controls and 225.0-6740.0 U/ml in 54 cases with the group of interstitial pneumonia. In the latter, the value in active cases was significantly higher than that in inactive cases (p < 0.0001). Based on above results, the optimal cut-off value was established as 500 U/ml by the ROC curves. By using the cut-off, serum KL-6 antigen can be used as a powerful diagnostic and prognostic marker for interstitial pneumonia.
Kobayashi
J
J
Department of Pulmonary Medicine, Jichi Medical School, Tochigi, Japan.
Itoh
Y
Y
Kitamura
S
S
Kawai
T
T
D000328:Adult; D000368:Aged; D000941:Antigens / Q000097:blood*; D000951:Antigens, Neoplasm; D015415:Biomarkers / Q000097:blood; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007124:Immunoenzyme Techniques; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D018396:Mucin-1; D009077:Mucins; D012016:Reference Values
D000941:Antigens; D000951:Antigens, Neoplasm; D015415:Biomarkers; D006023:Glycoproteins; C060192:MUC1 protein, human; D018396:Mucin-1; D009077:Mucins