Porphyria Diagnostics Part 3: Biochemical Protocols for the Diagnosis of Porphyrias

Porphyrins and porphyrin precursors are derived from intermediates in the heme biosynthetic pathway. Accurate measurement of these biochemicals is important for the diagnosis and monitoring of porphyrias. The biochemical protocols described in Part 3 include measurements of porphyrin precursors and porphyrins in the urine, feces, plasma, erythrocytes, and liver and determination of specific enzyme activities in erythrocytes and other cells. The basic protocols detailed here are needed for cost-effective first-line testing (i.e., screening) that emphasizes sensitivity for detecting or ruling out porphyrias in patients presenting with suggestive symptoms. They are also necessary for the more extensive testing that follows when first-line testing is positive.