Coproporphyrin III Unit Converter

Coproporphyrin III is an intermediate compound produced during heme biosynthesis, the process by which the body builds hemoglobin and other essential heme-containing proteins. It is one of two coproporphyrin isomers (I and III), with isomer III being the physiologically active form used in the heme pathway.

Small amounts of coproporphyrin III are normally excreted in urine, bile, and feces. Measuring its levels helps evaluate whether heme production is functioning properly and can flag conditions ranging from genetic porphyrias to heavy metal exposure.

Coproporphyrin III is typically measured alongside other porphyrin fractions. The ratio of coproporphyrin I to coproporphyrin III is also clinically important, as it can distinguish between specific liver and genetic conditions.

Coproporphyrin III is produced in the cytosol of cells during heme biosynthesis, primarily in erythroid precursors in the bone marrow (which account for over 80% of daily heme production) and in hepatocytes in the liver.