RELATIONSHIP BETWEEN FECAL SAMPLING TIMES AND SENSITIVITY AND SPECIFICITY OF IMMUNOCHEMICAL FECAL OCCULT BLOOD-TESTS FOR COLORECTAL-CANCER - A COMPARATIVE-STUDY

PURPOSE: The present study was conducted to assess the accuracy of thr ee testing methods using an immunochemical fecal occult blood test bas ed on the number of samples as the optimum means for screening of colo rectal cancer. METHOD: One hundred eighty-four patients with colorecta l cancer and 368 healthy controls served as the subjects for this stud y. Each subject was tested by an immunochemical fecal occult blood tes t for three consecutive days. For evaluation of the most desirable num ber of sampling times, we used the results of the first day for the on e-day method, results of the first and second days for the two-day met hod, and results of three consecutive days for the three-day method. S ensitivities and specificities of the three testing methods were evalu ated. RESULTS: Sensitivities of an immunochemical fecal occult blood t est were calculated as 67.9 percent for the one-day method, 88 percent for the two-day method, and 90.8 percent for the three-day method; sp ecificity was as follows: 97.5 percent for the one-day method, 95.6 pe rcent for the two-day method, and 92.1 percent for the three-day metho d. A significant difference in sensitivity was shown between the one-d ay and two-day and the one-day and three-day methods (P < 0.01); also, a significant difference in specificity was shown between one-day and three-day and two-day and three-day methods (P < 0.05). CONCLUSIONS: These results indicate that the two-day method is recommended for immu nochemical fecal occult blood testing as a means of screening for colo rectal cancer.