RENAL THRESHOLD FOR GLUCOSE IN NON-INSULIN-DEPENDENT DIABETIC-PATIENTS

Measurement of glycosuria is still widely used for home monitoring of glycaemic control in non-insulin-dependent diabetes (NIDDM). This meth od has been criticized because the renal threshold for glucose (RTglu) varies between subjects. In order to evaluate the validity of RTglu b y measuring corresponding measurements of blood and urine glucose in N IDDM patients, we studied the blood/urine glucose relationship in 24 N IDDM patients. RTglu estimated from 75 contemporary blood and urine gl ucose concentrations measured at home by each patient (h-RTglu) was co mpared with RTglu measured by a hyperglycaemic glucose clamp (c-RTglu) . H-RTglu and c-RTglu, being 7.6 mmol/l (range 5.5-12.4) and 10.3 mmol /l (6.2-12.3) respectively (P < 0.005), were weakly correlated (R(S)=0 .35, P=0.15). In conclusion, c-RTglu varies two-fold between NIDDM pat ients. RTglu detected by home monitored urine and blood glucose determ inations underestimates the true RTglu, probably due to the splay phen omenon. However, the method for detection of RTglu used by us seems of clinical relevance, since it reflects the individual blood glucose le vel at which glucose is detectable in the urine. (C) 1997 Elsevier Sci ence Ireland Ltd.