75025-7

LOINC code 75025-7 identifies "Coproporphyrin 3/Porphyrins.total in Stool". Total fecal porphyrins are markedly increased especially in active HCP (Hereditary Coproporphyria) and VP (Variegate Porphyria) and to a lesser extent in PCT (Porphyria Cutanea Tarda) and EPP (Erythropoietic Protoporphyria). Fecal porphyrins can be separated and measured individually by HPLC. Porphyrins with 2-4 carboxyl groups generally predominate in feces. These are excreted by the liver into the bile and then flow into the intestine. As with urine, it is most useful to measure the total amount of porphyrins in a fecal sample. If this is increased, then the laboratory should determine which porphyrins predominate rather than focus on the amount of each porphyrin. Fecal porphyrin determinations may be confounded by variations in fecal flow; most people have one or a few bowel movements daily and a "24 hour stool collection" is really not uniform from day to day. Substances in the diet and any internal bleeding into the stomach or intestines may also interfere.

This code measures Coproporphyrin 3/Porphyrins.total in Stool. It belongs to the CHEM class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.