False positive and negative hemoccult reactions on a normal diet and effect of diet restriction.
The reliability of Hemoccult, a guaiac-impregnated slide for detecting faecal occult blood, was assessed on both normal and restricted diets. Two-hundred-and-twenty-five faecal samples were obtained from 40 patients on a normal diet, and 115 samples from 20 patients on a restricted diet. A single Hemoccult I test was performed on each sample. Faecal blood was quantitated by 51Cr red cell labelling. On a normal diet, the false positive rate was 11%. This reduced to 2% on a high fibre diet free of red meat and raw fruit and vegetables. This false positive rate is lower than has been previously reported for other, more widely-used, occult blood tests. The overall false negative rate was 48%; this diminished with increasing faecal blood loss.
D004032:Diet; D005188:False Negative Reactions; D005189:False Positive Reactions; D005243:Feces / Q000032:analysis; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D009780:Occult Blood
D006454:Hemoglobins