Hemoglobin A1C, Blood (LAB90)

Hemoglobin A1c (HbA1c) is a marker of long-term glucose control, reflecting average blood glucose concentrations over the past ~90 days. It’s an important tool for monitoring diabetes management and adjusting treatment plans. The American Diabetes Association (ADA) recommends its use for both diagnosing and monitoring diabetes.

HbA1c measurements (for assays certified by the National Glycohemoglobin Standardization Program) exhibit excellent analytical performance. Glycemic control, as reflected by HbA1c, has demonstrated a strong capacity to predict complications such as retinopathy, nephropathy, and neuropathy.

After initial diagnosis, HbA1c measurements should be integrated with more short-term glycemic profiling. While the role for frequent (every 3 month) monitoring may have benefits for patients with newly diagnosed or uncontrolled diabetes in the adjustment of treatment plans, those with stable glycemic control do not require as frequent testing, and twice yearly will suffice.

• Measurement of HbA1c more frequently than every 3 months in patients leads to unnecessary medical costs without improving patient outcomes.
• Under-testing in patients with uncontrolled diabetes can miss opportunities for treatment optimization, especially in underserved populations.
• Testing patients with hemoglobinopathies for Hgb A1C is not reliable.

• HbA1c measurement more frequent than every 3 months in stable patients with diabetes is unlikely to add value to their clinical care.
• Assessment of glycemic control should be goal-driven and may include HgA1c, continuous glucose monitoring, and lifestyle cataloging.

1. American Diabetes Association. Standards of Medical Care in Diabetes—2023. Diabetes Care 2023; 46(Suppl 1): S1-S2. https://care.diabetesjournals.org/content/46/Supplement_1.

Aliases: Glycated Hemoglobin, A1c, Glycohemoglobin, T2DM, CGM, HgA1c