A rapid fecal immunochemical test for gastrointestinal bleeding detection in cynomolgus macaques (Macaca fascicularis)

Abstract

We used the Fecal Immunochemical Occult Blood Test (FIT) kit, a lateral flow immunochromatographic assay specific for human hemoglobin, on cynomolgus monkeys (Macaca fascicularis). We aimed to employ this test to detect gastrointestinal injury in captive animals at the National Primate Research Center of Thailand-Chulalongkorn University (NPRCT-CU). The cross-reactivity and sensitivity of the test for monkey blood were determined and compared with the human blood. The anti-human hemoglobin antibody of the FIT kit reacted with the monkey blood in a similar way as it did with humans and the intensity (T/C ratio) values between the two data sets closely correlated (R2 = 0.9324, p>0.05). Although the specificity for monkey blood was 4.2 times lower than for human blood, monkey blood with a dilution as low as 1:256,000 could be detected in monkey fecal samples. Thus, we used the FIT kit to determine the gastrointestinal adverse effects of the NPRCT excipient which was orally administered daily to four female cynomolgus monkeys for 28 days. A daily visual inspection of freshly defecated fecal samples did not detect any blood but with the high sensitivity of the FIT kit the presence of hemoglobin in the feces was shown once in three of the four monkeys (3 of the 112 specimens determined). In conclusion, the human-FIT can be an applicable tool for early detection of gastrointestinal injury in captive as well as wild cynomolgus monkeys. The advantage of this kit is that it requires non-invasive fecal sample collection, requires no additional equipment and gives results that can be read by the naked eye immediately.