[Sensitivity and specificity of alpha-1-antitrypsin and acid alpha-1-glycoprotein in colorectal carcinoma]

In a group of 80 patients with colorectal cancer and a control group of 91 persons and in 15 patients with acute diverticulitis of the sigmoid colon acid alpha-1-glycoprotein (AGP) and alpha-1-antitrypsin (AAT) were measured. The median of AAT in the carcinoma group was 3.34 g/l, in the control group 2.39 g/l. AGP was in the carcinoma group 1.19 g/l, in the control group 0.79 g/l. Both differences are significant. The sensitivities of AGP and AAT were compared with the sensitivities of CEA and CA 19/9 using ROC-curves. AAT and AGP have a distinctly lower sensitivity than CEA, but only on the basis of a high specificity of 95%. In the region of lower specificities AAT has the highest sensitivity. Therefore, the sensitivity of CEA for colorectal carcinoma is not reached by AAT and AGP, when a high specificity of the test is required. The relevance of AAT and AGP determinations is further reduced because in the diverticulitis group the levels were as high as in the carcinoma group.