hormonal and metabolic disorders
Acute Intermittent Porphyria
Diagnosis of Acute Intermittent Porphyria
Urine tests The severe digestive and neurologic symptoms of acute intermittent porphyria resemble symptoms of many more common disorders. Laboratory tests done on samples of urine taken during an attack show increased levels of two porphyrin precursors (delta-aminolevulinic acidand porphobilinogen). Levels of these precursors are very high during attacks and remain high in people who have repeated attacks. The precursors can form porphyrins, which are reddish. These porphyrins turn the urine red to red-brown. The color is especially evident after the urine specimen is exposed to light and air. Relatives without symptoms can be identified as carriers of the disorder by measuring the level of the deficient enzyme porphobilinogen deaminase in red blood cells or, with greatest certainty, by DNA testing. Diagnosis before birth is also possible but usually is not needed because most affected people never get symptoms. 