The clinical significance of glycated hemoglobin (HbA1c)

Glycated hemoglobin (HbA1c) is a core indicator that reflects long-term blood sugar control. Its clinical significance is mainly reflected in three aspects:diagnosing diabetes,Assess blood sugar control effectivenessandPredict risk of complications. HbA1c reflects the average blood sugar level in the past 2-3 months by detecting the degree of binding of hemoglobin and glucose in red blood cells, avoiding the volatility of a single blood sugar test. Both the World Health Organization (WHO) and the American Diabetes Association (ADA) regard HbA1c ≥ 6.5% as one of the diagnostic criteria for diabetes. In addition, it can help doctors adjust treatment plans and provide early warning of the possibility of cardiovascular, renal and other complications.

1. The “gold standard” for diagnosing diabetes

HbA1c is included in the diagnostic criteria for diabetes due to its stability. Compared with fasting blood glucose or oral glucose tolerance test (OGTT), HbA1c does not require fasting and is less affected by short-term diet or exercise. Studies have shown that when HbA1c ≥ 6.5%, the risk of diabetes increases significantly, while 5.7%-6.4% indicates prediabetes. For example,American Diabetes Association (ADA)It is pointed out that HbA1c testing can reduce the rate of missed diagnosis, especially for asymptomatic early-stage diabetes patients. Guidelines from many countries around the world, including Japan and Europe, recommend it as an auxiliary diagnostic tool.

2. “Monitor” for blood glucose management

For patients with established diabetes, HbA1c is a key indicator of the effectiveness of treatment options. The ADA recommends that most patients control HbA1c at <7%. Young patients can be more stringent (such as <6.5%), while elderly patients or patients with comorbidities can be appropriately relaxed. Clinical data shows that for every 1% reduction in HbA1c, the risk of microvascular complications is reduced by 37%. For example,UKPDS researchIt has been confirmed that intensive glycemic control (HbA1c ≤ 7%) can significantly reduce retinal and renal lesions. In addition, dynamic monitoring of HbA1c changes can help doctors adjust medications (such as insulin or oral hypoglycemic drugs) in a timely manner.

3. “Early warning signs” of complication risk

Long-term high HbA1c levels are closely associated with diabetic complications. Studies have shown that when HbA1c>8%, the risk of cardiovascular events increases by more than 50%, and the risk of neuropathy and delayed wound healing also increases significantly. For example,DCCT trialIt was found that patients whose HbA1c was controlled below 7.2% had a 76% reduction in the incidence of retinopathy. Therefore, regular detection of HbA1c is not only a need for blood sugar management, but also an important means to prevent serious consequences such as amputation and renal failure.

Summary and Outlook

HbA1c integrates long-term information on blood sugar control and provides an efficient and reliable basis for diabetes diagnosis and treatment. However, its detection may be interfered by factors such as anemia and hemoglobin variation, and needs to be combined with other indicators for comprehensive judgment. In the future, with the popularization of continuous glucose monitoring (CGM) technology, HbA1c may be combined with real-time blood glucose data to further optimize personalized treatment. At present, the world’s major testing equipment manufacturers includeRoche (Cobas series),Abbott (Alinity Series)andSiemens (ADVIA series), its products have passed international standardization certification (such as NGSP).

Quote sources:
1. American Diabetes Association (ADA) "Standards for the Diagnosis and Treatment of Diabetes" (2023)
2. World Health Organization (WHO) "Diagnostic Guidelines for Diabetes"
3. UKPDS study (1998) and DCCT trial (1993)
4. Manufacturer: Roche (Cobas c501), Abbott (Alinity c), Siemens (ADVIA 2400)