Health Library

PBG urine test

Porphobilinogen test; Porphyria - urine; PBG

Porphobilinogen (PBG) is one of several types of porphyrins found in your body. Porphyrins help form many important substances in the body. One of these is hemoglobin, the protein in red blood cells that carries oxygen in the blood. Porphyrins usually leave your body through urine or stools. If this process does not occur, porphyrins such as PBG can build up in your body.

This article describes the test to measure the amount of PBG in a urine sample.

I Would Like to Learn About:

How the Test is Performed

After you provide a urine sample, it is tested in the lab. This is called a random urine sample.

If needed, your health care provider may ask you to collect your urine at home over 24 hours. This is called a 24-hour urine sample. Your provider will tell you how to do this. Follow instructions exactly.

How to Prepare for the Test

Your provider may tell you to temporarily stop taking medicines that may affect the test results. Be sure to tell your provider about all the medicines you take. These include:

• Antibiotics and anti-fungal medicines
• Anti-anxiety medicines
• Birth control pills
• Diabetes medicines
• Pain medicines
• Sleep medicines

Never stop taking any medicine without first talking to your provider.

How the Test will Feel

This test involves only normal urination, and there is no discomfort.

Why the Test is Performed

This test may be done if your provider suspects porphyria or another disorder associated with an abnormal PBG level.

Normal Results

For a random urine sample, a negative test result is considered normal.

If the test is done on a 24-hour urine sample, the normal value is less than 4 milligrams per 24 hours (18 micromoles per 24 hours).

Normal value ranges may vary slightly among different lab. Some labs use different measurements or may test different specimens. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

An increased level of PBG in the urine may be due to:

• Hepatitis
• Lead poisoning
• Liver cancer
• Porphyria (several types)

Risks

There are no risks with this test.

Related Information

References

American Porphyria Foundation website. Tests for porphyria diagnosis. porphyriafoundation.org/for-patients/about-porphyria/testing-for-porphyria/tests-for-porphyria-diagnosis/. Accessed May 2, 2025.

Fuller SJ, Wiley JS. Heme biosynthesis and its disorders: porphyrias and sideroblastic anemias. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 39.

Hift RJ. The porphyrias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 194.

Review Date: 2/3/2025  

Reviewed By: Warren Brenner, MD, Oncologist, Lynn Cancer Institute, Boca Raton, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: verify here.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language.

© 1997- 2026 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

All content on this site including text, images, graphics, audio, video, data, metadata, and compilations is protected by copyright and other intellectual property laws. You may view the content for personal, noncommercial use. Any other use requires prior written consent from Ebix. You may not copy, reproduce, distribute, transmit, display, publish, reverse-engineer, adapt, modify, store beyond ordinary browser caching, index, mine, scrape, or create derivative works from this content. You may not use automated tools to access or extract content, including to create embeddings, vectors, datasets, or indexes for retrieval systems. Use of any content for training, fine-tuning, calibrating, testing, evaluating, or improving AI systems of any kind is prohibited without express written consent. This includes large language models, machine learning models, neural networks, generative systems, retrieval-augmented systems, and any software that ingests content to produce outputs. Any unauthorized use of the content including AI-related use is a violation of our rights and may result in legal action, damages, and statutory penalties to the fullest extent permitted by law. Ebix reserves the right to enforce its rights through legal, technological, and contractual measures.