Porphobilinogen (24 Hrs Urine)

Specimen Required

24 Hrs Urine

Fasting Required

Purpose of the Test

The porphobilinogen (PBG) urine test is ordered to diagnose or monitor certain medical conditions such as acute intermittent porphyria (AIP), a rare genetic disorder that affects the production of heme, an important component of red blood cells. This test measures the level of PBG in a 24-hour urine sample.

When this test is required

The porphobilinogen test may be ordered when a patient presents with symptoms suggestive of a porphyria, or when a family member has been diagnosed with a porphyria and other family members are at risk of having the same condition. It may also be ordered as part of a workup for unexplained abdominal pain or neurological symptoms.

What the Test Detects

Porphobilinogen is a substance that is produced during the synthesis of heme, a component of hemoglobin that is found in red blood cells. A urine test for porphobilinogen measures the amount of this substance excreted in the urine over a 24-hour period.

Preparation for the Test

There is no specific preparation needed for this test, but patients should inform their healthcare provider of any medications they are taking, as some medications can affect PBG levels. It is also recommended that patients avoid alcohol, smoking, and strenuous exercise during the 24-hour urine collection period.

Sample Requirements

A 24-hour urine sample is required for this test. The patient should collect all urine produced during a 24-hour period in a container provided by the laboratory. The container should be kept cool during the collection period and returned to the laboratory promptly.

Additional Notes

It is important to note that the presence of porphobilinogen in the urine is not specific to porphyria and may also be elevated in other conditions, such as lead poisoning or liver disease. Therefore, other tests may be needed to confirm a diagnosis of porphyria. Additionally, certain medications and foods can affect the results of the test and should be avoided prior to testing.

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