A new immunochromatographic fecal occult blood test (IOBT) is more sensitive in finding colorectal cancers and the adenomas (polyps) that lead to colorectal cancer than the more commonly used guaiac-based test (GOBT) according to research presented last week at the [World Congress of Gastroenterology](http://www.wcog2005.org/). The test, developed in Japan, is available in the US marketed as OC-Light.
Nearly 1,600 individuals, at average risk for colorectal cancer, completed both the IOBT and the GOBT. Overall, 8.4% of them had a positive result on the new test compared to 3.4% on the older guaiac test. 1,9% tested positive on both. 154 of the 161 patients testing positive on either test had follow-up colonoscopy. In addition, 222 people not testing positive had colonoscopy.
During colonoscopy 26% of patients with a positive test had a large adenoma or polyp, 9% had cancer. Of those testing negative, 2% had adenomas and none had cancer.
The newer IOBT was more sensitive than GOBT in finding 50% of the advanced adenomas, 58% of precancerous conditions, and 100% of the cancers. The guaiac test sensitivity was 9% for adenomas, 12% for precancer, and 23% for cancer. Both tests were highly specific — more than 92% for all three conditions.
The test is simple to use — a sample of feces is collected in a small bottle and a test strip placed inside. One blue band means the test is negative for hidden blood in stool, a second band means that the test is positive. No special diet is necessary before the test.
Enrique Quintero, MD presented the study findings. He heads the gastroenterology department at the Hospital Universitario des Canarias, La Laguna, Tenerife, Spain.
Dr. Quintero pointed out the the study results are based on a single test and that repeated tests would increase sensitivity.
[Read more about the study results on *Medscape.*](http://www.medscape.com/viewarticle/512826?src=hp43.infocus)