How is Hba1c is 10.7 when my FBS is 129 and PPBS is 190?

Answer by Dr. Albana Greca Sejdini, MD, MMedSc

Medically reviewed by Dr. Ruden Cakoni, MD, Endocrinologist | Last reviewed: July 2026

Hi Caron,

Your confusion is understandable because fasting glucose, post-meal glucose, and HbA1c measure different parts of glucose metabolism. A person may have normal fasting readings but significant glucose rises after meals. Therefore, normal morning glucose does not exclude prediabetes or diabetes.

How the A1C Ranges Are Interpreted

If you do not have unmistakable symptoms or a hyperglycemic emergency, diabetes diagnosis usually requires two abnormal test results. When A1C is at or above 6.5% but fasting glucose is below 126 mg/dL, current guidance recommends repeating the test that is above its diagnostic threshold. If two properly performed laboratory A1C results are 6.5% or higher, diabetes can be diagnosed even when fasting glucose remains normal.

Why Can A1C Change From 5.6% to 7.0%?

A1C reflects average glucose exposure over approximately the previous two to three months, with greater influence from the most recent weeks. A real change may occur after changes in diet, activity, weight, illness, steroid treatment, diabetes medicine, or glucose control.

A large difference can also occur when tests were performed by different methods or when something affects red blood cells. Possible factors include iron-deficiency or other anemia, recent bleeding or transfusion, kidney or liver disease, pregnancy, hemoglobin variants, and medicines or conditions that change red-cell survival. Point-of-care or home A1C tests should not be used by themselves to diagnose diabetes.

What Should You Do Next?

1. Collect the dates, exact A1C values, laboratories, fasting readings, and post-meal readings.


2. Ask for a repeat venous laboratory A1C using an NGSP-certified method, particularly if the previous result was 6.5%–7.0%.


3. Have laboratory fasting plasma glucose checked. Your clinician may also recommend a 75-gram oral glucose tolerance test when fasting and A1C results remain unclear.


4. Measure post-meal glucose at a consistent time—usually 1–2 hours after the first bite—not at random intervals. Home post-meal readings can reveal patterns but do not diagnose diabetes.


5. If A1C and glucose remain substantially different, ask whether anemia, altered red-cell turnover, kidney or liver disease, a hemoglobin variant, or another source of test interference should be evaluated.

You can compare your readings with the normal blood sugar and diagnostic ranges and learn more about interpreting post-meal glucose.

What Can You Do While Waiting for Confirmation?

Do not start or reject medication based only on one result. Treatment depends on the confirmed diagnosis, symptoms, cardiovascular and kidney risk, pregnancy status, and other health factors.

• Replace sugary drinks and large portions of refined carbohydrates with water, non-starchy vegetables, lean protein, and controlled portions of high-fiber carbohydrates.


• Combine carbohydrates with protein or healthy fat to make meals more balanced.


• Be physically active regularly if your clinician says exercise is safe.


• Avoid smoking, sleep adequately, and work toward a healthy weight when appropriate.

Related Questions

• Why does my HbA1c not match my fasting and post-meal readings?


• Does an A1C of 5.6% mean prediabetes?


• Can I perform an A1C test at home?


• Why do my glucose results appear contradictory?

Related Resources

• A1C Blood Sugar Levels Explained


• HbA1c to Average Glucose Calculator


• Blood Tests Used to Diagnose Diabetes


• Blood Sugar Levels by Time of Day

References

• American Diabetes Association: Diagnosis and Classification of Diabetes—2026


• NIDDK: The A1C Test and Diabetes


• CDC: A1C Test for Diabetes and Prediabetes

Medical disclaimer: Educational only—not personal medical advice.