Es. Kilpatrick et al., Plasma 1,5-anhydroglucitol concentrations are influenced by variations in the renal threshold for glucose, DIABET MED, 16(6), 1999, pp. 496-499
Aims Measurement of serum 1,5-anhydroglucitol (1,5AG) concentrations has be
en proposed as an alternative to HbA(1c) as both a marker of diabetic glyca
emic control and as a screening rest for diabetes. The sugar competes with
glucose for renal tubular reabsorption, so hyperglycaemia leads to reduced
serum 1,5AG concentrations through increased urinary loss. This study has s
ought to establish whether plasma 1,5AG can be influenced by nut only hyper
glycaemia, but by variations in renal threshold fur glucose.
Methods Thirty-eight pregnant women (median age 30 years, range 20-43) foun
d to be normoglycaemic after a 75-g carbohydrate load had plasma 1,5AG and
urine glucose measured.
Results Using multivariate analysis, the presence and degree of detectable
glycosuria at 2h post glucose load was strongly predictive of a low plasma
1,5AG concentration (P=0.0012) independently of lasting plasma glucose (P=0
.96), 2h glucose (P=0.029), subject age (P=0.97) and gestation (P=0.36). Th
us, when matched fur plasma glucose areas under the glucose load curve, 16
glycosuric subjects had significantly lower 1,5AG concentrations compared t
o 16 nonglycosuric ones (median 1,SAG 46 mu mol/l (IQR 30-56) vs. 72 mu mol
/l (IQR 55-79, P=0.017).
Conclusions People with the same glucose tolerance may demonstrate variable
plasma 1,5AG concentrations depending on their renal threshold for glucose
. This inherent characteristic is likely to limit the usefulness of the tes
t when monitoring or screening for diabetes.