Comparative and Stability Study of Glucose Concentrations Measured in Sodium Fluoride and Serum Separator tubes

Abstract

IntroductionSodium fluoride/potassium oxalate (NaF/KOx) tubes were once regarded as the gold-standard tubes for glucose analysis. Even though their ineffectiveness in immediately inhibiting glycolysis has been reported in several studies especially in the first 1-4hours, they are still used in our clinical Biochemistry laboratory for glucose measurement. However in its absence, only SSTs are employed for glucose measurement. AimTo determine whether SSTs can replace NaF/KOx tubes for laboratory-based measurement of blood glucose and to assess the stability of glucose concentrations for 3 days period MethodsDuring the study period (1 March to 11 April, 2015), a total of 50 paired samples collected separately in NaF/KOx tubes and SSTs from healthy adult participants in the Gambia Adults Reference Intervals Study (GARIS) project were used as the project sample size. The samples were analysed within 2hours, and at 24hours, 42hours and 72hours time-points following blood collection and separation using Vitros 350 dry chemistry analyser. The GARIS samples were treated as clinical samples. ResultsThere was no significant difference in the mean glucose concentrations between the two tubes (Mean difference= 0.06mmol/L; P=0.38) recorded in the different time-points. Using growth trajectory and mixed effects model, the study data showed no significant change in the glucose concentrations (p=0.25) for three days period. ConclusionsThe study confirms that SSTs can produce similar glucose results when employed in the absence of NaF/KOx tubes. Besides, the glucose concentrations were stable in both tubes for three days when the samples were separated within two hours and refrigerated in 2-8{degrees}C.