ROC analysis of diagnostic performance utilizing serum antiproteases in cancer patients

Assessment of the accuracy of diagnostic procedures is made independent of diagnostic criteria by means of a receiver-operating-characteristics (ROC) curve. We performed ROC analysis for the major serum antiproteases: alpha-1-antitrypsin (A1AT) and alpha-2-macroglobulin (A2M), in 99 cancer patients compared with 71 normal individuals. A1AT and A2M were significantly higher in cancer patients (p less than 0.0005). By comparing true positive and false positive rates for different serum levels, ROC analysis showed that serum A1AT quantification seems more useful in clinical practice than serum A2M.