Role of D-Mannose as an Antiglycolytic Agent to Eliminate Preanalytical Error in Glucose Testing

Introduction: Correct assessment of glucose is required for diagnosis of diabetes and monitoring of antihyperglycaemic therapy in adults as well monitoring neonatal hypoglycaemia. As per American Diabetes Association, sodium fluoride alone is an unreliable antiglycolytic agent in vitro due its ineffective action during first 4 hours of sample collection. Aim: To evaluate the efficacy of mannose as compared to conventional antiglycolytic agent for blood glucose estimation and to assess its use as a preservative for other routine biochemical analytes. Materials and Methods: The study was carried out in three steps. Fifteen samples of plasma were aliquoted into 5 parts. One was without any additive and in other four D-mannose was added in concentration of 1,2,3 and 5 mg/mL. Blood glucose was analysed immediately, at 1.5 hours, 3 hours and 5 hours to optimize the concentration of D-mannose. Fifteen serum samples were aliquoted into 2 parts, one without any additive and the other with D-mannose at a concentration of 3 mg/dL. Both were subjected for routine biochemistry to check for any interference by D-mannose in analysis. Fifteen samples were collected in heparin (with mannose added in concentration of 3mg/dL), plain tube, EDTA and sodium fluoride vacutainers. Blood glucose and other routine analytes were measured immediately, at 1.5 hrs and 3 hrs to compare D-mannose with other preservatives. Results were analysed using Student’s t-test. Results: Optimal concentration of D-mannose was found to be of 3 mg/mL. D-Mannose showed a less decrease of blood glucose at the end of 3 hrs compared to sodium fluoride. D-Mannose does not interfere with estimation of any analytes except potassium. Creatine kinase was found to be lower with EDTA compared to other preservatives. Conclusion: D-Mannose is an ideal preservative for blood glucose. All routine analytes (except potassium) can be estimated from a single vacutainer containing D-mannose at a concentration of 3 mg/dL.