A cost-effective analysis of the optimum number of stool specimens collected for immunochemical occult blood screening for colorectal cancer

This study was carried out to assess, from the viewpoint of cost-effectiven ess, the optimum number of faecal specimens to collect for use in immunoche mical occult blood testing as a means of screening for colorectal cancer. 3 300 asymptomatic individuals were subjects of this study. They gave samples for an immunochemical faecal occult blood test, monohaem and colonoscopy w as carried out during a medical check-up. For evaluation of the optimum num ber of sampling specimens, the results of the first day of sampling, those of the first and second days, and those of samples taken for 3 consecutive days were considered as the single-day method, the 2-day method and the 3-d ay method respectively. The average cost to detect 1 patient with colorecta l cancer, the detection rate and the false-positive rate of these three fae cal sample collection methods were evaluated. The average costs for one can cer case detected were calculated as $3630.68 for the single-day method, $3 350.65 for the 2-day method and $4136.36 for the 3-day method, respectively . The detection rate and the false-positive rate were calculated as 47 and 3.5% for the single-day method, 82 and 4.7% for the 2-day method and 88 and 5.3% for the 3-day method, respectively. This detection rate was significa ntly different between the single- and the 2-day methods, as well as betwee n the single- and the 3-day methods (P < 0.05). No significant differences in the false-positive rate amongst the three testing methods were observed. This analysis suggests that a 2-day faecal collection method is recommende d for immunochemical occult blood screening by Monohaem from the aspects of cost-effectiveness and diagnostic accuracy. (C) 2000 Elsevier Science Ltd. All rights reserved.