by Ashish
(Bhopal)
QUESTION: My fasting blood sugar is 80.1 mg/dL and my PP blood sugar is 186.8 mg/dL. My wife's fasting blood sugar is 121.9 mg/dL and her PP blood sugar is 166.8 mg/dL. Are these normal?
Your fasting glucose of 80.1 mg/dL is within the normal fasting range. Your wife's fasting glucose of 121.9 mg/dL is in the prediabetes range if it was a laboratory fasting test after at least 8 hours without calories.
Your PP values of 186.8 mg/dL and 166.8 mg/dL need more context. A two-hour reading after an ordinary meal is not the same as the two-hour oral glucose tolerance test used to diagnose diabetes. If these were formal 75-g OGTT results, both would fall in the 140–199 mg/dL prediabetes range.
I would recommend that your wife have a repeat fasting laboratory glucose and HbA1c. Because your own post-meal value was 186.8 mg/dL despite a normal fasting level, an HbA1c or other laboratory screening test would also be reasonable.
Answer by Dr. Albana Greca, MD, MMedSc
Hi Ashish,
The fasting and post-meal results should be interpreted separately. A normal fasting value does not always rule out abnormal glucose handling after meals, and a post-meal home reading cannot by itself diagnose diabetes.
| Person | Fasting | PP | Interpretation |
|---|---|---|---|
| You | 80.1 | 186.8 | Fasting normal; PP needs context |
| Your wife | 121.9 | 166.8 | Fasting in prediabetes range; PP needs context |
| Fasting plasma glucose | Interpretation |
|---|---|
| Below 100 mg/dL | Normal range |
| 100–125 mg/dL | Prediabetes range |
| 126 mg/dL or higher | Diabetes range when confirmed as recommended |
Your fasting value of 80.1 mg/dL is normal. Your wife's 121.9 mg/dL is above normal and falls within the prediabetes range if it was a properly performed laboratory fasting test.
Our guide to normal fasting blood sugar levels explains these ranges in more detail.
PP usually means postprandial, or after eating. The meaning depends on exactly when the sample was taken and whether it followed an ordinary meal or a formal oral glucose tolerance test.
For diagnosis, the standard two-hour test uses a measured 75-g glucose drink. In that test:
| 2-hour OGTT result | Interpretation |
|---|---|
| Below 140 mg/dL | Normal range |
| 140–199 mg/dL | Prediabetes range |
| 200 mg/dL or higher | Diabetes range when confirmed as recommended |
If your 186.8 and your wife's 166.8 were simply measured two hours after a normal meal, I would not apply the OGTT diagnostic cutoffs directly. However, the readings are high enough to justify proper laboratory screening, particularly when your wife's fasting glucose is already 121.9 mg/dL.
Yes. Some people maintain a normal fasting glucose but have difficulty controlling glucose after meals. This can occur early in impaired glucose tolerance or diabetes, which is why fasting glucose alone does not identify every case.
An HbA1c can help because it reflects average glucose over roughly the previous 2–3 months. A formal OGTT may also be useful if your doctor needs more information.
Diabetes can be diagnosed with a fasting plasma glucose of 126 mg/dL or higher, an HbA1c of 6.5% or higher, or a two-hour 75-g OGTT result of 200 mg/dL or higher. In the absence of clear symptoms or a hyperglycemic crisis, abnormal results generally need confirmation.
A blood sugar level chart can help distinguish diagnostic ranges from readings taken at other times of day.
Ashish, your fasting glucose of 80.1 mg/dL is reassuring, but I would not ignore the PP value of 186.8 mg/dL. Your wife's fasting glucose of 121.9 mg/dL deserves follow-up because it falls in the prediabetes range.
The most useful next step for both of you is laboratory testing, especially HbA1c, rather than trying to diagnose diabetes from one pair of fasting and post-meal readings.
Medical review: Dr. Ruden Cakoni, MD, Endocrinologist
Last reviewed: August 2026.
Educational safety note: This answer is for general diabetes education only and does not replace personal medical advice, diagnosis, or treatment. Do not start or change medicines, supplements, diet, or exercise plans without discussing them with your healthcare provider.
Click here to post comments or follow up
Ask the Doctor now? Simply click here to return to Diabetes Test and Levels.