Increased urinary porphobilinogen

What it means

The concentration of porphobilinogen in the urine, normalized for urine concentration, is above the upper limit of normal.

Increased porphobilinogen (PBG) in urine is pathognomonic of an attack of acute porphyria (acute intermittent porphyria, variegate porphyria, hereditary coproporphyria); the absence of increased urinary PBG in a suspected attack excludes the diagnosis.

Rare diseases that can present with this6

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category