Sorted By Test Name - Mayo Medical Laboratories

PBGD_
88925
drugs), alcohol, infection, starvation, heavy metals, and hormonal changes may precipitate crises. AIP is
inherited in an autosomal dominant manner. At-risk family members of patients with a biochemical
diagnosis of AIP should undergo appropriate testing. Timely diagnosis is important as acute episodes of
AIP can be fatal. Treatment of AIP includes the prevention of symptoms through avoidance of
precipitating factors. Fortunately, >80% of individuals with PBGD deficiency remain clinically
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)
80% of individuals with PBGD deficiency remain clinically
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.
Current as of January 4, 2013 7:15 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 1443