πGST is located in the distal tubules of the human kidney whereas alpha GST (πGST) is confined mainly to the proximal tubules. πGST is released into the urine of normal individuals as confirmed by enzyme immunoassay. Any event which precipitates distal tubular damage may cause increased release of πGST into urine and elevations of urinary GST levels have been shown to be indicative of distal tubule damage in renal transplant rejection, nephrotoxicity, infection, diabetes and chronic renal injury. The release of πGST has been shown to be associated with proximal tubular damage, thus simultaneous measurement of πGST and πGST may allow discrimination between proximal and distal tubular damage.

The Pi GST EIISA is a quantitative enzyme immunoassay. The test procedure is based on the sequential addition of sample, antibody-enzyme conjugate and substrate to Microassay wells coated with anti-πGST IgG. The resultant color intensity is proportional to the amount of πGST. The assay range is 1.25 – 40μg/L.