Most people assume diabetes is easy to diagnose. You take a blood test, get a number, and that’s it. But in real life, it’s messier. There are different diabetes tests, and they don’t always tell the same story. That’s where confusion starts, for patients.The fasting blood sugar test is often the first step. You don’t eat for a few hours, give blood, and wait for the result. Simple enough. But blood sugar isn’t static. Stress, poor sleep, illness, or even a bad night’s rest can push the number up. So someone might test high one morning and normal a week later. That back-and-forth can make people think everything’s fine when it’s not.
Then there’s the HbA1c test, which looks at average blood sugar over about three months. On paper, it sounds more reliable. But it has blind spots. Many people can get misleading results. So you might feel awful, have classic diabetes symptoms, and still be told your A1c is “borderline” or “normal.”Sometimes the fasting blood sugar is normal but the HbA1c is not. This one really throws people off. You test your fasting sugar and it looks fine, maybe even “perfect.” And then your HbA1c comes back high. So which one do you believe? All this mixed data can slow things down. Doctors may wait to “recheck in a few months.” Patients may downplay symptoms because one test looked okay. Meanwhile, blood sugar problems keep brewing quietly. By the time diabetes is clearly diagnosed, complications may already be starting.TOI Health spoke to Dr. Santosh Kumar Agrawal, Director – Internal Medicine, Yatharth Super Speciality Hospital Faridabad about this confusion and the doctor has cleared it in simple words.The cancers doctors see most often after menopause
Many people have normal fasting sugar but high HbA1c—can you explain why these numbers sometimes don’t match?
A person’s fasting blood sugar shows the amount of glucose in their bloodstream at the time of the test, while HbA1c reflects a person’s average blood sugar levels over the last two to three months. Therefore, if a person has a lot of post-meal blood glucose spikes during the day, experiences nighttime rises, or has unstable blood glucose levels, their HbA1c level can be elevated even though their fasting glucose readings are normal.
What everyday habits or hidden factors can cause HbA1c to rise even when fasting sugar looks normal?
The repeated spikes in blood glucose can be attributed to multiple factors including, large amounts of processed carbohydrates, sugary drinks, eating late at night, poor quality sleep, experiencing chronic stress, and physical inactivity. Some medical conditions such as anemia, vitamin B 12 deficiency, renal failure and medications can also raise a person’s HbA1c level, even when their fasting blood glucose values are in the normal range.
Are there specific tests or monitoring strategies people should follow if their fasting sugar is fine but HbA1c is high?
Postprandial monitoring of blood glucose, administering an oral glucose tolerance test, and using continuous glucose monitor devices can be utilized to diagnose hidden spikes in blood glucose. Pairing an individual’s regular HbA1C testing with the measurement of their fasting and post-meal blood glucose provides a comprehensive view of their overall metabolic health, as well as the individual’s daily blood glucose patterns.
Can diet, exercise, or small lifestyle changes bring HbA1c down, even if fasting sugar is normal?
Yes, eating a well-balanced meal that is high fiber, protein and healthy fats; minimizing the intake of processed carbohydrate foods; engaging in post-meal walking; participating in regular exercise; managing stress levels; and enhancing the quality of one’s sleep will all contribute to lowering blood glucose spikes. Additionally, making small, consistent modifications can reduce an individual’s average blood glucose level and thereby lead to a gradual reduction in their HbA1c level.Medical experts consulted This article includes expert inputs shared with TOI Health by: Dr. Santosh Kumar Agrawal, Director – Internal Medicine, Yatharth Super Speciality Hospital FaridabadInputs were used to explain why some people have normal fasting sugar but high HbA1c.
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