by Chandra
(Pune)
Question: I had my complete body checkup two days back. My fasting Sugar level is 122 mg/dl and the PP level after two hours of breakfast (steamed rice food and orange juice) the level is 103 mg/dl. The doctor says its a pre diabetes stage and advised me for HbA1C test.
My question is why my fasting level is high when compared to PP level a total diff of around 20 mg/dl.
Six month back my fasting was 117 mg/dl and PP 132 mg/dl but Doc didn't advised me anything and said everything is normal. My Dad has diabetes.
Your fasting glucose of 122 mg/dL is in the prediabetes range, not the diabetes range. The earlier fasting result of 117 mg/dL was also in the prediabetes range. A two-hour value of 103 mg/dL after breakfast is reassuring, but it does not cancel the fasting results or prove that you do not have prediabetes.
Fasting glucose and after-meal glucose measure different parts of glucose regulation. The HbA1c test your doctor recommended is appropriate, and your family history makes follow-up especially important.
Answer by Dr. Albana Greca Sejdini, MD, MMedSc
For a properly performed laboratory fasting plasma glucose test after at least eight hours without calories, the usual diagnostic categories for nonpregnant adults are:
Therefore, both 117 and 122 mg/dL fall within the prediabetes range. You cannot be diagnosed with diabetes from these values alone, but they should not be described as completely normal.
This pattern can occur for several reasons:
Your body may release enough insulin after breakfast to bring glucose down by two hours even though fasting glucose remains mildly elevated.
A two-hour reading after rice and orange juice is a post-meal measurement. It can provide useful information, but the amount and absorption of carbohydrate are not standardized.
The diagnostic two-hour glucose test uses a measured 75-gram glucose drink. Its usual cutoffs are below 140 mg/dL for normal glucose tolerance, 140–199 mg/dL for prediabetes and 200 mg/dL or higher for diabetes when confirmed. Those criteria should not be applied directly to an ordinary breakfast.
HbA1c estimates average glucose exposure over roughly the previous two to three months. General diagnostic categories are:
HbA1c and fasting glucose may not always agree. If the results are discordant, your clinician may repeat the abnormal test, order another laboratory fasting glucose or consider a formal oral glucose tolerance test. Conditions such as anemia, altered red-blood-cell turnover and some hemoglobin variants can also affect HbA1c interpretation.
Because your father has diabetes and your fasting glucose has been elevated twice, regular monitoring is important even if HbA1c is currently below the prediabetes threshold.
Do not diagnose or treat yourself from one post-meal number. Seek prompt medical assessment if you develop excessive thirst, frequent urination, unexplained weight loss, vomiting, marked weakness, confusion or repeatedly much higher glucose readings.
Answered by: Dr. Albana Greca Sejdini, MD, MMedSc
Medically reviewed by: Dr. Ruden Cakoni, MD, Endocrinologist
Last reviewed: July 2026
Medical disclaimer: Educational only—not personal medical advice. Diagnosis and treatment should come from a qualified clinician who knows the patient’s medical history.
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