What Is Porphobilinogen Test – Indications, Procedures, Results

Last updated: February 8, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 2 min read

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.

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 so that the results are accurate.

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 drugs
Anti-anxiety drugs
Birth control pills
Diabetes medicines
Pain medicines
Sleep medicines

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

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 laboratories. Some labs use different measurements or may test different specimens. Talk to your doctor 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.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area later with a custom field named _rx_references.

Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.