Serum [Gamma]-Glutamyltransferase and Risk of Disease (Editorial‪)‬

Serum [gamma]-glutamyltransferase (GGT) has long been used as a liver function test and a marker of excessive alcohol use; in recent years our knowledge of GGT's physiological functions has expanded and several important epidemiological associations have been reported. The paper by Ryu et al. in this issue of Clinical Chemistry (1) extends the range of conditions predicted by GGT to include chronic kidney disease (CKD). Such prospective associations between GGT and disease raise issues in both pure and applied science; first, the pathological significance of the wide range of GGT--disease risk associations, and second, the effects that this information may have on the clinical or preventive use of GGT determinations. CKD is an increasingly common and important condition (2). Existing laboratory markers include glomerular filtration rate estimated from serum creatinine, sex, age, and race (eGFR), and the presence of proteinuria. Because CKD tends to progress, these markers also have predictive value. Defining the pathological role of GGT in CKD will require more investigation. GGT may be a marker of the pathological process or even a contributor, but in either case, GGT is a novel predictor of CKD that could contribute to early intervention and improved outcomes.