Question: What is (are) Porphyria ?
Answer: Heme is a red pigment composed of iron linked to a chemical called protoporphyrin. Heme has important functions in the body. The largest amounts of heme are in the form of hemoglobin, found in red blood cells and bone marrow. Hemoglobin carries oxygen from the lungs to all parts of the body. In the liver, heme is a component of proteins that break down hormones, medications, and other chemicals and keep liver cells functioning normally. Heme is an important part of nearly every cell in the body.
Source: NIDDK

Question: How to diagnose Porphyria ?
Answer: A health care provider diagnoses porphyria with blood, urine, and stool tests. These tests take place at a health care providers office or a commercial facility. A blood test involves drawing blood and sending the sample to a lab for analysis. For urine and stool tests, the patient collects a sample of urine or stool in a special container. A health care provider tests the samples in the office or sends them to a lab for analysis. High levels of porphyrins or porphyrin precursors in blood, urine, or stool indicate porphyria. A health care provider may also recommend DNA testing of a blood sample to look for known gene mutations that cause porphyrias.
Source: NIDDK