Patent ID: 8349573

Claim:
A lateral flow immunoassay device for simultaneous detection of transferrin and hemoglobin in a sample, comprising a test strip which comprises: (1) a sample site for applying said fecal sample; (2) a conjugate site downstream of said sample site, wherein a labeled anti-transferrin antibody and a labeled anti-hemoglobin antibody are deposited at said conjugate site; (3) a test zone downstream of said conjugate site, wherein said test zone comprises two separate sites, one of which is immobilized with an anti-transferrin antibody, and the other is labeled immobilized with an anti-hemoglobin antibody; and (4) a control site wherein a control antibody is immobilized thereto, wherein the test strip is calibrated such that a positive signal appears test site immobilized with said anti-hemoglobin antibody when hemoglobin is present in said sample at higher than the predetermined value of 0.2 μg/ml for hemoglobin, and a positive signal appears in the test site immobilized with said anti-transferrin antibody when transferrin is present in said sample at higher than the predetermined value of 30 ng/ml for transferrin, such that the signals produced from a test sample permit a differential diagnosis of bleeding from the upper GI tract versus the lower GI tract.