Porphobilinogen synthetase - red cell

Last updated: Wednesday, 07, April, 2004
Item Process
Specimen

2 mL blood in lithium heparin tube.

Method

Spectrophotometry.

Reference Interval

Varies with method: generally 10-26 U/L.

Application

Decrease in the enzyme has been used as an indicator of increased lead exposure, but this has been largely superseded by measurement of blood lead.

The enzyme is also decreased in the very rare genetic disease, plumboporphyria.

Interpretation

Inhibition of the enzyme commences with levels of blood lead unlikely to cause acute symptoms.

Plumboporphyria is an autosomal recessive disease with virtual absence of enzyme activity; heterozygotes have about 50% activity.

Reference

Thunell S. J Clin Chem Clin Biochem 1987; 25: 5-14.