Ultrasensitive time-resolved immunofluorometric assay of glutathione transferase alpha in serum.

Glutathione transferase Alpha (GSTA) is a very sensitive marker of acute centrilobular liver damage. We purified glutathione transferases from human liver and separated the isoenzymes. Polyclonal rabbit antibodies specific for Alpha-class isoenzymes were produced and labeled with Eu(3+)-chelate. We set up a sandwich-type time-resolved immunofluorometric assay (TR-IFMA) to measure GSTA in serum. The detection limit was 0.03 microgram/L, and measuring range was from 0.03 to 100 micrograms/L. The reference range for serum GSTA in this assay was 0.7-6.0 micrograms/L for women and 0.7-14 micrograms/L for men. This TR-IFMA is practical, and the modified rapid assay can be completed in 3 h. Therefore it is applicable for diagnostic purposes in acute liver damage, e.g., associated with drug toxicity or hypoperfusion of the liver.