|
|
||||||||
1 Department of Medicine, Division of Endocrinology, University Hospital of Helsinki, 00029 HUS Helsinki, Finland.
aAddress correspondence to this author at: Department of Medicine, University Central Hospital of Helsinki, Biomedicum-Helsinki, Box 700, 00029 HUS Helsinki, Finland. E-mail raili.kauppinen{at}hus.fi.
Background: Acute intermittent porphyria (AIP) is a metabolic disease with clinical manifestations that mimic other abdominal, neurologic, or mental crises. We studied the diagnostic accuracy of current laboratory tests during an acute attack and in remission.
Methods: Since 1966, we have studied all known Finnish AIP patients (n = 196) and their families (n = 45) and identified the porphobilinogen deaminase (PBGD) mutation in each family. Diagnoses or exclusions of AIP were based on clinical data (including family history), biochemical tests, and in 239 cases, mutation testing. We retrospectively evaluated the diagnostic accuracy of erythrocyte PBGD activity, urinary excretion of porphobilinogen (PBG) and
-aminolevulinic acid, and urinary and fecal excretion of porphyrins in these patients.
Results: Measurement of urinary PBG identified all 35 AIP patients studied during an acute attack. The mean excretion of PBG was 50-fold above the reference interval, although the intraindividual increases were modest (1.6- to 4.0-fold). In the mutation-screened population, urinary PBG analysis identified only 85% of 81 AIP patients studied during remission, but by ROC curve analysis it was nonetheless the best of the biochemical tests. It was increased
2-fold in 29% of healthy relatives. Erythrocyte PBGD activity was decreased in only 84% of AIP patients, with results within the reference interval mainly in the variant form of AIP; it was decreased in 23% of healthy relatives.
Conclusions: Measurement of urinary PBG is the best biochemical test for AIP, although it is unspecific and does not distinguish AIP from other acute porphyrias. Because the acute increase in PBG is often modest, the medical history, signs, and symptoms must be evaluated carefully during an acute attack. In addition, because biochemical analyses often remain indeterminate in remission, mutation analysis is needed to exclude or confirm the diagnosis of AIP.
The following articles in journals at HighWire Press have cited this article:
![]() |
A. K. Aarsand, H. Boman, and S. Sandberg Familial and Sporadic Porphyria Cutanea Tarda: Characterization and Diagnostic Strategies Clin. Chem., April 1, 2009; 55(4): 795 - 803. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. K. Aarsand, P. H. Petersen, and S. Sandberg Estimation and Application of Biological Variation of Urinary {delta}-Aminolevulinic Acid and Porphobilinogen in Healthy Individuals and in Patients with Acute Intermittent Porphyria. Clin. Chem., April 1, 2006; 52(4): 650 - 656. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Sandberg and G. H. Elder Diagnosing Acute Porphyrias Clin. Chem., May 1, 2004; 50(5): 803 - 805. [Full Text] [PDF] |
||||
![]() |
B. Lumbreras-Lacarra, J. M. Ramos-Rincon, and I. Hernandez-Aguado Methodology in Diagnostic Laboratory Test Research in Clinical Chemistry and Clinical Chemistry and Laboratory Medicine Clin. Chem., March 1, 2004; 50(3): 530 - 536. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |