Hepatology 73 (5): 1736 - 1746, 2021. doi: 10.1002 / hep.31460 Diagnosis of Acute Porphyrias Urine screen for porphobilinogen (PBG) and creatinine If urine results are positive, quantitative urinary ALA and PBG and creatinine determinations For confirmation of acute hepatic porphyria (AHP) and to determine type, genetic analysis Prior to the wide-spread availability of accurate genetic testing, measurement of activity of PBG deaminase [aka HMBS] in red blood cells was used for confirmation of the diagnosis of AIP.