Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

PBGU
82068
unaffected throughout their lives. The biochemical diagnosis of AIP is made during an acute episode by
demonstrating increased urinary excretion of PBG, the substrate of PBGD. During asymptomatic periods,
urinary PBG may be informative; however, a normal or only slightly increased result should be repeated
during a subsequent crisis. In addition, the diagnosis of AIP can be facilitated through the measurement of
PBGD enzyme activity in erythrocytes, though 5% to 10% of affected individuals exhibit normal
erythrocyte PBGD activity. For additional information on the recommended order of testing, the
following algorithms are available in Special Instructions: -Porphyria (Acute) Testing Algorithm
-Porphyria (Cutaneous) Testing Algorithm For additional information regarding porphyrias, see The
Heme Biosynthetic Pathway in Special Instructions.
Useful For: Confirmation of a diagnosis of acute intermittent porphyria (AIP) Diagnosis of AIP
during latent periods
Interpretation: Acute intermittent porphyria (AIP) is 1 of the very few diseases where a single
laboratory test can be diagnostic (porphobilinogen deaminase [PBGD] levels or =7.0 nmol/L/sec
6.0-6.9 nmol/L/sec (indeterminate)