Porphyrins are a group of compounds defined by their chemical structure. They are an integral part of certain proteins found in the body such as hemoglobin, myoglobin, and specific enzymes. Porphyrin test is used to help diagnose and monitor a group of disorders called porphyrias. It is also used to help rule out the presence of a porphyria in someone who presents with neurologic/psychiatric or cutaneous symptoms.Most porphyrin tests detect and measure the by-products of heme synthesis. The synthesis of heme is a step-by-step process that requires the sequential action of eight different enzymes. If there is a deficiency in one of these enzymes, a bottleneck forms and precursors (porphyrins such as uroporphyrins, coproporhyrins, and protoporhyrins) build up in the body fluids and tissues and are excreted in urine. Depending upon the patient’s age and symptoms, a test for urine porphyrins and/or the free erythrocyte protoporphyrin test should be ordered when a patient presents with blisters, scarring, redness, or other skin lesions in sun-exposed areas. Porphyria is usually associated with abdominal pain, nausea, constipation, depression, confusion, hallucinations, and seizures. INCREASED porphyrin levels may be seen with Nonacute Porphyrias, which include Congenital Erythropoietic Porphyria, Porphyria Cutanea Trarda, Toxic Porphyria, Hepato-erythropoietic Porphyria, and Protoporphyria. Acute Porphyria includes Acute Intermittent Porphyria, and ALA dehydratase deficiency. Porphyrins are also increased in porphyrias producing both neurological and cutaneous manifestations.