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Clinical Chemistry

Hexokinase Method

The hexokinase method is a diagnostic test that accurately measures glucose concentration in biological fluids. This method is commonly used to estimate plasma glucose levels and is highly accurate and robust. Measuring plasma glucose concentration is essential for assessing a patient's glycemic state, which can be helpful in various medical conditions, such as diabetes mellitus, stroke evaluation, and acute trauma. When other methods, such as blood-prick test, HbA1c, or oral glucose tolerance t

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  • A plasma glucose level of less than 40 mg/dL or more than 399 mg/dL is critical, according to CLSI guidelines.
  • The laboratory and the hospital must have a robust communication system for notifying the treating clinician or the ward’s nursing station so that life-saving measures can commence early.
  • If timely measures are not taken to restore the glucose level, it can lead to serious and permanent damage to the brain, causing coma and death.
  • Random plasma glucose (RBG) is frequently prescribed in the emergency department and intensive care units when handling critically ill patients.
  • The hexokinase method is a diagnostic test that accurately measures glucose concentration in biological fluids.
  • Measuring plasma glucose concentration is essential for assessing a patient's glycemic state, which can be helpful in various medical conditions, such as diabetes mellitus, stroke evaluation, and acute trauma.
  • When other methods, such as blood-prick test, HbA1c, or oral glucose tolerance tests, are not feasible, the hexokinase method may be the best option for developing a management plan.
  • Plasma glucose levels measured in different physiological scenarios, such as fasting, and 2-hour post-prandial are utilized to screen, diagnose, and monitor pathological conditions.
  • The hexokinase method is an exact and accurate method for plasma glucose estimation.
  • The definitive method for glucose determination is isotope dilution mass spectrometry (ID-MS).
  • Plasma glucose estimation is prescribed in different clinical and physiological scenarios.
  • Screening and diagnosis of diabetes mellitus, impaired glucose tolerance, and fasting hyperglycemia are based on the plasma glucose level of random, fasting, or 2-hour post-prandial blood specimen.
  • A glucose tolerance test is also performed to diagnose and confirm the diagnosis of diabetes mellitus (DM).
  • Diagnosis of gestational diabetes mellitus (GDM) is based on plasma glucose levels at different time intervals after the glucose load.
  • The hemolyzed specimen having more than 0.5 g of hemoglobin is unsuitable for analysis by the hexokinase method.
  • Hypertriglyceridemia and hyperbilirubinemia also create interference and provide falsely elevated values of plasma glucose.
  • Sample blanking is necessary to nullify the effect of triglyceride and bilirubin in the plasma glucose.
Diabetes Mellitus (DM) Diagnosis Criteria (ADA)
Diagnosis of DM is based on the cut-off values for plasma glucose levels in fasting, 2 hours post 75 g glucose load (oral glucose tolerance test - OGTT), and values of HbA1c fraction of glycated hemoglobin.
Impaired Fasting Glucose
FPG value between 100 to 125 mg/dL (5.6 to 6.9 mmol/L)
Impaired Glucose Tolerance
OGTT value between 140 to 199 mg/dL (7.8 to 11.0 mmol/L)
Critical Plasma Glucose Level (CLSI)
less than 40 mg/dL or more than 399 mg/dL
  • Advising these individuals to adopt a healthy, balanced diet and an active lifestyle is crucial.
  • When other methods, such as blood-prick test, HbA1c, or oral glucose tolerance tests, are not feasible, the hexokinase method may be the best option for developing a management plan.
  • Due to higher time requirements and relatively less accuracy and precision than enzymatic methods, chemical methods such as Folin Wu and O-Toluidine are less utilized in clinical laboratories.
  • Many POCT analyzers, including blood-gas instruments, measure glucose concentrations using the glucose oxidase method.
  • Urine dipsticks are widely used to screen for glucose in the urine.
  • The definitive method for glucose determination is isotope dilution mass spectrometry (ID-MS).
  • Gestational diabetes mellitus (GDM) is when a woman without a history of DM develops hyperglycemia during her pregnancy.
  • The causes of hypoglycemia are different in different age groups.
  • Other causes of hyperglycemia include endocrine disorders such as Cushing syndrome, pheochromocytoma, acromegaly, medications such as glucocorticoids, parenteral nutrition, intravenous dextrose infusion, pancreatic disorders that reduce the functionality of the endocrine pancreas such as pancreatitis, pancreatic malignancy, and hemochromatosis.
  • Regular monitoring of disease progression and the impact of dietary and lifestyle changes is recommended.
  • Close-looped communication where the values are read back to the notifying facility is essential.
  • Communication documentation must also be maintained regarding the date and time of call attempts, names and designation of the person making and receiving calls, details communicated, and the hospital’s superior officer notified in case of failed communication attempts.
  • Plasma glucose level is under effective hormonal and metabolic control in a healthy person.
  • Any disturbance in this balance can alter plasma glucose levels through hypoglycemia or hyperglycemia.
  • A plasma glucose level of less than 70 mg/dL is hypoglycemia.
  • However, signs and symptoms of hypoglycemia may not be visible until the plasma glucose levels drop to 55 mg/dL or lower.
  • Signs and symptoms of hypoglycemia are mainly due to a reduced supply of glucose to the central nervous system (CNS) and activation of the sympathetic nervous system.
  • review
    Hexokinase Method. StatPearls [Internet] — Amit D. Sonagra, Muhammad Zubair, Anita Motiani — StatPearls Publishing, 2024

Decision support only. Verify against local protocols and current labeling. Source: www.ncbi.nlm.nih.gov