Lag period of fluoride oxalate in plasma glucose stabilization

Abstract

Introduction: A major problem in the accurate measurement of glucose is its decrease in concentration due to erythrocytic glycolysis after sampling. Eliminating this problem requires the use of an anti-glycolytic agent that can be added to the sampling tubes to stabilize the glucose level before analysis.

Aim: This research was aimed at determining the lag period of fluoride oxalate in plasma glucose stabilization at Ahmadu Bello University Teaching Hospital Shika –Zaria.

Methods: Five milliliters of venous blood sample was collected from 40 subjects (20 diabetic and 20 apparently healthy) each patient and 1.2ml each was dispensed into four separate fluoride-oxalate (20mg/ml) tubes and were centrifuged at 0, 30, 60, and 120 minutes time to obtain plasma respectively. The glucose concentrations of the separated samples was analysed by glucose oxidase method.

Results: The mean glucose concentrations at 0, 30, 60 and 120 minutes were 9.92±0.84, 9.64±0.83, 9.48±0.83, 9.47±0.82 and 5.38±0.33, 5.12±0.34, 4.95±0.32 and 4.95±0.32 for diabetic and normal samples respectively. No significant decrease (p>0.05) were observed in the mean plasma glucose concentrations between samples separated at 60 minutes compared to 120 minutes in both group of subjects.

Conclusion: This shows that the fluoride-oxalate solution almost completely inhibit the loss of plasma glucose 60 minutes after mixing it with the blood. This was observed in both the normal and diabetic samples. This showed that a lag period of about 1 hour (from 0 to 60 minutes period ) is required by fluoride-oxalate solution to completely stabilize plasma glucose. When fluoride-oxalate solution is used for plasma glucose assay, the blood sample should be separated immediately to prevent a significant loss of the plasma glucose due to its long lag period.