In vitro Validation Assessment of a Fecal Occult Blood Protein Test for Horses

A commercially available equine fecal blood test (FBT) claims to be able to detect the presence of blood proteins (albumin and hemoglobin) in manure. The purpose of this study was to determine the FBT test sensitivity, specificity, positive and negative predictive values (PPV, NPV), lower threshold of detection, time to obtain a visual positive result, effect of temperature and result stability in lab and field conditions. The FBT was assessed for its sensitivity and specificity for detecting pure albumin and hemoglobin at two temperatures over a range of concentrations. Time to result was measured for up to 60 minutes. PPV and NPV were assessed by measuring albumin and hemoglobin in manure from 13 pleasure horses over 25 days. Laboratory tests of hemoglobin alone, albumin alone, and hemoglobin and albumin combined were tested over a range of concentrations from 0.0125 ppm to 50 ppm. In the field study, fresh (within 30 minutes) manure was sampled and tested for proteins using the FBT. The FBT was both sensitive and specific to hemoglobin and albumin. The effect of cold temperature on time to a positive result at 15 minutes was not significant. Results were stable for up to 60 minutes. The field study showed evidence that the appearance of blood proteins in manure was intermittent, and that three tests on consecutive days provided a much better PPV and NPV. It is concluded that this FBT had high specificity, sensitivity, PPV, NPV, was equally functional at low and moderate temperatures, provided a rapid (within 15 minutes) and stable (for up to 60 minutes) reading. Its use in the field is simple and effective.