Which glucose method is considered to be the reference method?

Which glucose method is considered to be the reference method?

• A. Glucose oxidase
• B. o-Toluidine
• C. Hexokinase
• D. Glucose dehydrogenase

Answer: (C)

The method using hexokinase is considered the reference because it provides the highest specificity and accuracy for glucose measurement. In this approach, glucose is first phosphorylated by hexokinase in the presence of ATP to form glucose-6-phosphate. This step is highly specific for glucose, with minimal interference from other sugars that might be present in a clinical sample. Then glucose-6-phosphate is oxidized by glucose-6-phosphate dehydrogenase, using NADP+, to produce NADPH. The amount of NADPH generated is directly proportional to the glucose concentration, and it’s measured spectrophotometrically at 340 nm. This two-enzyme, stoichiometric reaction gives a true reflection of the glucose amount in the sample and is robust against common interferences that affect other methods. Because of its precision, specificity, and traceability, this enzymatic sequence is used as the standard reference method, while other methods (like glucose oxidase, o-toluidine, or glucose dehydrogenase approaches) can be more susceptible to interferences or less specific.

The method using hexokinase is considered the reference because it provides the highest specificity and accuracy for glucose measurement. In this approach, glucose is first phosphorylated by hexokinase in the presence of ATP to form glucose-6-phosphate. This step is highly specific for glucose, with minimal interference from other sugars that might be present in a clinical sample. Then glucose-6-phosphate is oxidized by glucose-6-phosphate dehydrogenase, using NADP+, to produce NADPH. The amount of NADPH generated is directly proportional to the glucose concentration, and it’s measured spectrophotometrically at 340 nm. This two-enzyme, stoichiometric reaction gives a true reflection of the glucose amount in the sample and is robust against common interferences that affect other methods. Because of its precision, specificity, and traceability, this enzymatic sequence is used as the standard reference method, while other methods (like glucose oxidase, o-toluidine, or glucose dehydrogenase approaches) can be more susceptible to interferences or less specific.