What Does High Hemoglobin A1c but Normal Blood Sugar Mean?

Many diabetes patients results may show unexpectedly high A1c levels while blood sugar levels is normal.
This is the second problem about A1c we discuss here.
The first issue was: Normal A1c and elevated blood sugar levels
Doctors and patients may still confused abut Hgb A1c results that seen elevated when the fasting and 2hPPG results are normal in the same day.
Many reasons are behind the abnormal correlation between Hemoglobin A1c levels and blood glucose levels:

Hemoglobin A1c Vs BS levels

Firstly, let’s revise some essential information about hemoglobin A1c results if you’re already know you can skip this chapter.

What does it mean when your A1c levels are elevated?

Typically, The definition of a high A1c level is A1c more than 6.5% which diagnose diabetes mellitus according to American diabetes association.
Don’t miss: Full A1c Chart
For instance; Hgb A1c% 7.0 and fasting sugar result is 130 mg/dl, the interpretation for these levels indicate mildly uncontrolled type 2 DM.
While in an example like this:
Hemoglobin A1c level of 8.0% but fasting blood glucose level comes 100 mg/dl (normal: up to 110), the A1c is elevated while the fasting test tells that there’s no diabetes.
Remember that: A1c is a calculated value of an “average” of B.G. levels for a time of about 90 – 120 days.
Back to: What Does A1c Stand For?
So that; the patient asks us;

Can I become a diabetic with normal glucose levels and high A1C?

The answer:
A high A1c means uncontrolled or failure of diabetes management for 3 months ago, while normal sugar test results mean good control.
The Possible reasons behind abnormal hemoglobin A1c with normal sugar levels:
First assumption:

High Hemoglobin A1c Normal Blood Sugar due to an error in the blood sugar tests:

Starvation before a blood sugar test can lower sugar results falsely:
If you fast more than 8 hours for fasting sugar test the body utilize the blood sugar and thus appear below the actual elevated reading.
When you intake less than 75 g of glucose before the post-postprandial glucose test, it may decrease the actual elevated value by mistake.
If you have taken a high dose of sugar-lowering medication before fasting:
You may taken the treatment at the incorrect time or the dose is higher than prescribed by your doctor.
If you have taken the treatment prior to testing PPBG:
For type 2 pills or type 1 insulin injection, mark the time of starting the eating or the time after drinking the 75 g of glucose to avoid mistaken time errors.
You can increase your knowledge of: Blood Glucose Levels Chart

Second; errors affect hemoglobin A1c test

High carbs diet could put A1c at the prediabetes level
Raisins are pack full of natural sugary carbs, and sugar free cookie’s still have carbs and consequently the carbs turn to sugar.
You can measure A1c by home meters many times to come up with an idea about that.
If I were you, I would get a low cost glucometer with strips from walmart to know how high you go after eating carbs

Biological causes of high A1c but Normal BG levels

The rate of red blood cell turnover is variable from person to person:
As some studies found that there are people who turnover their red blood cells in about 80 days,
they expected that those people have less sugar attached to their RBCs, thus they see lower-than-expected A1C levels.
while those with longer lifetime span of RBCs may have a turnover of 140 days, thesy accumulate more sugar on their red cells and therefore see higher-than-expected A1C levels.
Who is prone to short turnover rate and false low A1c are:
Anemic patient have low red blood cells count and low hemoglobin level, so that the A1c is falsely decreased.
Do you know: What Does Anemic Mean?
Patients with pre-existing diabetes: DM patient have short-live red blood cells, which in turn lead to false low hemoglobin A1c results.
People who donate blood or have any internal bleeding:
Their blood cells generated at a faster way and therefore the new RBCs have no glucose attached yet, this fact will lead to unreal low Hgb A1c values.
Who’s prone to long turnover and false high A1c are:
Non-Diabetes persons have longer RBCs lifespan than those with diabetes, which may or may not alter the real HbA1c results.
You can see All FAQs of Hemoglobin A1c Test.

Do you have type 3C Diabetes?

Type 3 Diabetes mellitus is a less-know diabetes in who suffering from acute pancreatitis or chronic pancreatic disease
Doctors may misdiagnose type 3CDM as type 2.
Type 3C diabetes comes after pancreatectomy, necrosis of pancreas,  or inflammation of pancreas which lead to insufficient insulin levels in the blood.
By taking anti-diabetes drugs the sugar level can be normal at the day of testing but due to decreased insulin availability the accumulated sugar increase and increase the A1c level at the end.


High A1c as it can’t compared to the blood glucose levels.
Low C-peptide test is diagnostic to type1 DM and type 3 C DM along with high blood sugar.
Elevated Pancreatic enzymes is a marker of pancreatitis and thus diagnostic for type 3C DM along with other Diabetes tests.


Type 3c diabetes requires insulin therapy urgently which may be delayed when type 2 misdiagnosis occurred.
Full guide.

New Explanation about Type 3C diabetes will come next week, stay tuned and subscribe.

Dr.Megan Ralf

A Medical laboratory Scientist who devoted his life to medical and laboratory sciences, writes his everyday expertise dealing with various pathological conditions through laboratory diagnosis of different body fluids, also participating in many workshops for first aids, infection control, and urgent care. Also Dr Megan Ralf coaching many medical teams.

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