The purpose of this study was three-fold: 1) to define the effects of
obesity and Type 2 diabetes on plasma lactate concentrations; 2) to re
late changes in plasma lactate concentration to plasma glucose and ins
ulin concentrations; and 3) to evaluate the effect of differences in b
lood sample processing on plasma lactate determination in a disparate
population group. To accomplish this, fasting plasma lactate concentra
tions were determined in 30 volunteers (1O non-obese individuals with
normal glucose tolerance, 10 obese individuals with normal glucose tol
erance, and 10 obese individuals with Type 2 diabetes) on blood drawn,
processed, and maintained in a variety of ways. Results demonstrated
that fasting plasma lactate measurements were least confounded when bl
ood was drawn without the subject << hand pumping >> following venous
occlusion, the samples maintained on ice at 4 degrees C until precipit
ated with perchloric acid, and kept as this temperature until lactate
concentration was determined. Under these conditions, plasma lactate c
oncentration was lowest in the non-obese group with normal glucose tol
erance (0.81 +/- 0.07 mmol/L), highest in the obese subjects with Type
2 diabetes (1.46 +/- 0.14 mmol/L), and intermediate in obese individu
als with normal glucose tolerance (1.17 +/- 0.13 mmol/L). All three gr
oups were significantly different from each other. In addition plasma
lactate concentrations were associated with both fasting plasma glucos
e and glycated haemoglobin concentrations.