RESUMEN
Increased gama-glutamyl transpeptidase (GGT) levels have been observed in pacients with several types of liver diseases. However, since GGT activity can be inhibited or incrased by several substances, the interpretation of these increased levels should be made with caution. The present study was designed to determine plasma GGT activity in blood samples obtained from 24 adult volunters (13 males and 11 females aged 20 to 40 years) with the use of three different anticoagulants, i.e., ethylenediaminetetraacetic acid (EDTA), calcium fluoride and calcium citrate, and to compare it with GGT activity in serum obtanied from the same blood samples. Serum GGT activity wa significantly higher than plasma GGT activity (P < 0.001) and singnificantly higher in men than in women (P < 0.05), though plasma GGT activity was similar for both sexes