EVALUATION OF A FIRST-LINE SPECTROPHOTOMETRIC SCREENING-TEST FOR INCREASED FECAL PORPHYRIN CONCENTRATION

We compared a spectrophotometric screening test measuring faecal porph yrin concentration with an HPLC method. There was a good overall corre lation between both methods although some scatter was observed. ROC pl ot analysis of the screening test leads to a cut-off value of 35 nmol porphyrin per g faeces, wet weight with a sensitivity of 97% and a spe cificity of 96%. These results indicate that the screening test is qui te useful for detection of increased total faecal porphyrin concentrat ion, but less useful in accurate measurement of increased total faecal porphyrin concentration.