Clinical study of a new fecal occult blood test using a combination assay of hemoglobin and transferrin.

The applicability of a new immunological fecal occult blood test in which hemoglobin (Hb) and transferrin (Tf) are simultaneously assayed was evaluated. The mean absorbance and standard deviation (510/630 nm) obtained by this test was 0.840 +/- 0.805 in 51 fecal samples from patients with colon cancer, 0.248 +/- 0.305 in 95 samples from patients with colon polyps, and 0.104 +/- 0.053 in 110 samples from control patients; these values differed significantly (P less than 0.005). Hb and Tf concentrations were separately determined in the same fecal samples, and qualitative evaluation was performed with a cutoff value of 5.1 micrograms/g feces for Hb and 0.4 micrograms/g feces for Tf. Hb or Tf was positive in 41 of the 51 samples in the colon cancer group, 33 of the 95 in the colon polyp group, and 3 of the 110 in the control group. Qualitative analysis of the values obtained by the combination assay of Hb and Tf with a cutoff value of 0.200 revealed positive rates of 41/51 in the colon cancer group, 33/95 in the colon polyp group, and 4/110 in the control group. These results suggest the usefulness of a combination assay of Hb and Tf as a fecal occult blood test.