Abstract

HANO GARCIA, Olga Marina; CASTELLANOS GUTIERREZ, Mavié; CALZADILLA BERTOT, Luis  and  VILLA JIMENEZ, Oscar Manuel. Validation of an immunochemical technique for the detection of fecal occult blood. Rev Cubana Invest Bioméd [online]. 2014, vol.33, n.1, pp. 19-33. ISSN 0864-0300.

Background: colorectal cancer is preventable and responds effectively to treatment when diagnosed at an early stage. Determination of fecal occult blood is a method used to screen for early colorectal cancer and its precursor lesion, the adenoma. Objectives: 1) determine the validity and reproducibility of the RapiLat-Hemo immunochemical test to diagnose colorectal cancer and adenomas, and compare it with the reference reagent (SPIN-FOB), 2) describe the most frequent endoscopic findings in patients with positive fecal occult blood, 3) describe the location of colorectal cancer in patients with positive RapiLat-Hemo immunochemical tests. Methods: A validation study was conducted of a new Cuban immunochemical test (RapiLat-Hemo) to detect FOB. The study sample was composed of 161 patients attending colon consultation at the Institute of Gastroenterology of Havana in the period 2008-2010 who were undergoing colonoscopy and met the inclusion criteria. All patients underwent FOB determination (RapiLat-Hemo), and results were correlated with those of the reference reagent and colonoscopy. Results: There was a predominance of the female sex and the ≤ 60 age group. The test for detection of colorectal cancer had a sensitivity of 88.2% and a specificity of 92.4%. For detection of ≥10 mm adenomas, sensitivity was 60.0% and specificity 85.3%. Conclusions: The test showed adequate validity and reproducibility for the diagnosis of colorectal cancer and ≥ 10 mm adenomas. There was concordance with the reference reagent (SPIN-FOB). The most common endoscopic findings were polyps, colorectal cancer and diverticula. The most common colorectal cancer location in patients with positive fecal occult blood was the most distal segments of the colon.

Keywords : fecal occult blood; colonoscopy; cancer; colon; validation; sensitivity; specificity.

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