Platform
Company
Immunology & Autoimmune
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Currently under review
Pending specialist review and validation.
This test measures hexacarboxyporphyrins in a urine sample. Porphyrins are natural chemicals your body makes when producing heme, an essential part of hemoglobin and many enzymes. Hexacarboxyporphyrins are one of several porphyrin types that can spill into urine when the heme pathway is disrupted or when the liver is stressed.
It is usually performed as part of a urine porphyrin fractionation panel and is commonly reported relative to urine creatinine. Using the creatinine ratio helps account for how concentrated or diluted your urine is, so results are more comparable from person to person.
Doctors use this test to help evaluate suspected porphyria, a group of conditions that affect the heme pathway and can cause skin sensitivity, blistering, abdominal pain, or nerve symptoms. Certain liver conditions can also raise urine porphyrins, so the result can provide clues about whether your liver or the heme pathway is involved.
Results from this test are interpreted together with other porphyrin fractions and related tests to sort out the type and cause of the problem. It can also be used to monitor response to treatment in some porphyrin disorders and to check for triggers such as alcohol, estrogen therapy, or other factors that stress the liver.
A higher-than-expected result may suggest a disturbance in heme production or liver function, but it does not diagnose a specific disorder by itself. Your clinician will review the full porphyrin profile, your symptoms, and other labs such as delta-aminolevulinic acid and porphobilinogen, and may add plasma porphyrin testing, stool porphyrins, or genetic testing if needed.
If your level is unexpectedly elevated, do not stop medications on your own. Some drugs, alcohol, infections, or hormonal changes can temporarily affect porphyrin levels. Your care team may repeat testing, adjust timing to when symptoms are present, or check related liver and kidney tests. A normal or low result is usually reassuring, and next steps depend on your symptoms and the rest of your evaluation.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Porphyrins are light sensitive. Urine should be collected in a light-protected container, kept cool, and transported promptly. Exposure to heat or light can degrade porphyrins and lead to misleading results.
Results are reported relative to creatinine to correct for dilution. Very dilute urine or very low creatinine can make ratios appear higher or lower than expected. Follow collection instructions and tell your clinician if you were unusually dehydrated or overhydrated.
Some medicines, alcohol use, and estrogen therapies can increase porphyrin excretion. Never stop a medication without medical advice; instead, share a full list of drugs and supplements so interpretation can account for possible effects.
Cholestasis, hepatitis, or other liver stress can raise urinary porphyrins. Kidney impairment can alter creatinine and porphyrin handling, affecting ratios and interpretation.
In some porphyrias, abnormalities are more detectable during symptomatic periods. If initial testing is unrevealing but suspicion remains, your clinician may repeat the test when symptoms occur.
Porphyrin patterns can differ in children and during pregnancy. Your lab uses age-appropriate interpretation, and your clinician may consider pregnancy status or other conditions when reviewing results.
References