Colonoscopic evaluation of immunochemical fecal occult blood test for detection of colorectal neoplasia

BACKGROUND/AIMS: This study was carried out to assess the validity of three testing methods of immunochemical occult blood according to the number of collection times as a means for colorectal cancer screening. METHODOLOGY: Four thousand six hundred and eleven asymptomatic individuals, who received both an immunochemical occult blood test with a three-day met hod and colonoscopy during a medical checkup, served as subjects for this s tudy. For evaluation of the desirable number of sampling times, we used the results of the first day for the 1-day method, the results of the first an d second days for the 2-day method, and the results of three-consecutive da ys for the S-day method. Sensitivities and specificities of these three tes ting methods were evaluated. RESULTS: Sensitivities and specificities for colorectal cancer were calcula ted to be 56% and 97% for the 1-day method, 83% and 96% for the 2-day metho d, and 89% and 94% for the 3-day method, respectively, showing a significan t difference in sensitivity between the 1-day and the a-day methods, as wel l as the 3-day method (p<0.01), and in specificity between the 1-day as wel l as the 2-day and 3-day methods (p<0.05). CONCLUSIONS: These findings indicate that the immunochemical fecal occult b lood test is useful for the diagnosis of colorectal cancer, and that 2-day testing is recommended as a means of screening for colorectal cancer.