Porphyrias: Lab Test

1st order laboratory parameters – obligatory laboratory tests.

  • Detection of specific porphyria precursor stages in urine – qualitative urine test for porphobilinogen (PBG); if positive, quantitative measurements of porphobilinogen (PBG) and delta-aminolevulinic acid (ALA).
    • Acute intermittent porphyria (AIP):
      • Urine staining in air? If red → evidence of acute porphyria, before and during an attack.
      • Measurement of porphobilinogen deaminase (PBG-D) and delta-aminolevulinic acid deaminase (ALA-D) activity in erythrocytes (red blood cells).
      • Ehrlich aldehyde assay: add one drop of urine to 1 ml of Ehrlich reagent → if a red coloration occurs, AIP is present.
      • Analysis of fecal porphyrins
    • Porphyria cutanea tarda (PCT):
      • Porphyrin concentrations (uro- and heptacarboxyporphyrin) in urine and plasma [↑]
      • Isocoproporphyrin in stool → pathognomonic (evidencing disease).
      • Liver biopsy (tissue sample of the liver).
    • Erythropoietic porphyria (EPP):
      • Examination of heparin blood for free protoporphyrin (precursor of heme).
  • Electrolytescalcium, chloride, potassium, magnesium, sodium, phosphate.
  • Laboratory parameters to exclude acute organic disorders.

Notes:

  • Acute porphyrias show elevated levels only during attacks. In this case, PBG and ALA levels are at least 5 times higher than normal.
  • If necessary, determine the type of porphyria by genetic analysis.
  • A genetic test can determine the risk of disease for relatives and offspring. Genetic counseling centers help here.