Algorithm for diagnosis of acute porphyria and use of hemin in patients with symptoms suggesting an acute porphyria attack

Urine PBG may be tested by a screening method on-site (semiquantitative result, if available) or measured in a specialized laboratory (quantitative result, available in days to weeks). If available, a rapid method is extremely helpful because treatment can be initiated based on a positive result, and a negative result makes the diagnosis of an acute porphyria very unlikely. However, all symptomatic patients with suspected acute porphyria should have quantitative PBG, total porphyrins, and creatinine measured from the same sample. Because the results of quantitative testing are not known for days to weeks, we also order ALA and total porphyrins on the same urine sample. Urine creatinine is measured to allow normalization (results expressed per gram of creatinine). Refer to UpToDate topics on acute porphyrias for further details of diagnosis and treatment, and patterns of plasma and fecal porphyrin elevation.