From the Guidelines
Blood glucose levels should be measured through blood samples for immediate assessment, while Hemoglobin A1c testing is recommended every 3-6 months for long-term diabetes management. For people with diabetes, regular monitoring using blood samples is recommended, with frequency depending on their treatment regimen 1. Urine glucose testing is less reliable as glucose only appears in urine when blood levels exceed the renal threshold, making it unsuitable for detecting hypoglycemia or normal glucose levels. Hemoglobin A1c testing measures glycated hemoglobin in red blood cells, providing an average blood glucose level over the past 2-3 months rather than a current reading. This makes it valuable for long-term diabetes management but not for immediate glucose assessment. White blood cells are not used for glucose measurement in clinical practice.
Key Points to Consider
- Blood samples provide immediate glucose data
- HbA1c testing offers a long-term perspective on glycemic control
- Urine glucose testing has limitations and is not suitable for all patients
- The frequency of blood glucose monitoring and HbA1c testing should be individualized based on the patient's treatment regimen and glycemic control 2, 1 ### Methods of Glucose Monitoring
- Capillary blood glucose: recommended for self-monitoring of blood glucose (SMBG) in patients with diabetes 2
- HbA1c: recommended every 3-6 months to evaluate overall glycemic control 1
- Urine glucose testing: less reliable and not recommended for routine monitoring
- Continuous glucose monitoring (CGM): can detect hyperglycemia and hypoglycemia that are not easily recognized by traditional monitoring methods 2
From the Research
Blood Glucose Levels Measurement
- Blood glucose levels can be measured through various methods, including tissue sample, urine sample, hemoglobin, or white blood cells 3, 4, 5, 6 ### Hemoglobin A1c (HbA1c) Measurement
- HbA1c is a measure of erythrocyte hemoglobin glycation, reflecting mean glycemia for the previous 3 months 3
- HbA1c levels can be affected by certain conditions, such as hemolytic anemia or aplastic anemia 3
- The recommendation is to measure HbA1c every 3-6 months, with a target level of < 7% 3 ### Relationship between HbA1c and Blood Glucose Levels
- Higher HbA1c levels are correlated with ketosis in patients with type 2 diabetes mellitus (T2DM) 5
- The relationship between continuous glucose monitoring (CGM) estimated HbA1c and mean glucose differs between type 1 diabetes (T1D) and T2D cohorts 6 ### Diagnostic Thresholds for HbA1c
- In patients with newly diagnosed T2DM, an HbA1c threshold of 10.1% (87 mmol/mol) is optimal for screening for ketosis 5
- In patients with previously diagnosed T2DM, an HbA1c threshold of 8.6% (70 mmol/mol) is optimal for screening for ketosis 5