Type of Diabetes for Fasting Blood Sugar Of 8.6!
by nazmul
(Bangladesh. dhaka)
Question
I have no 8.6 fasting blood sugar level. What type of diabetes am I suffering?
Additional reading supplied: BLOOD SUGER FASTING: 197Mgms/100ml.
—Nazmul, Dhaka, Bangladesh
Quick Answer
Nazmul, the unit must be clarified. If your fasting result was 8.6 mmol/L, it equals approximately 155 mg/dL. If it was 197 mg/dL, that equals approximately 10.9 mmol/L. Both are above the laboratory fasting threshold used to diagnose diabetes.
However, a glucose number cannot tell whether you have type 1, type 2, or another form of diabetes. A home-meter result also cannot confirm the diagnosis by itself. Arrange prompt laboratory fasting glucose and HbA1c testing, followed by classification based on your history and, when needed, antibody or C-peptide tests.
Answer by Dr. Albana Greca, MD, MMedSc
Hello Nazmul,
The first problem is the unit. A result of 8.6 is usually reported in mmol/L, not mg/dL. A true glucose of 8.6 mg/dL would represent an extreme medical emergency and is almost certainly not what was intended.
Does This Result Mean Diabetes?
For nonpregnant adults, a laboratory fasting plasma glucose of 126 mg/dL or higher, equivalent to 7.0 mmol/L or higher, meets a diagnostic criterion for diabetes. Therefore, fasting results of 8.6 mmol/L or 197 mg/dL are in the diabetes range.
If you do not have unmistakable symptoms or a hyperglycemic emergency, the diagnosis usually requires confirmation with a second abnormal result. This may be a repeated fasting laboratory test, an HbA1c of 6.5% or higher, or another accepted diagnostic test. Our guide to blood tests for diabetes explains how fasting glucose, HbA1c, random glucose, and the oral glucose tolerance test differ.
A home glucose meter is valuable for monitoring but is not accurate enough to diagnose or exclude diabetes. If this was a meter result, take the meter and strips to your appointment and obtain laboratory confirmation.
What Type of Diabetes Could It Be?
The glucose level shows the degree of hyperglycemia, not the diabetes type.
- Type 1 diabetes is caused by autoimmune destruction of insulin-producing beta cells. It can begin in children or adults and may present with thirst, frequent urination, weight loss, ketones, or rapid deterioration.
- Type 2 diabetes combines insulin resistance with insufficient insulin production. It is the most common type and can occur at any age.
- Other forms include diabetes caused by pancreatic disease, certain medicines, genetic conditions, and diabetes during pregnancy.
It is inaccurate to decide that a young person has type 1 diabetes or an older person has type 2 diabetes based only on age. Read more in our type 1 diabetes guide and overview of diabetes types and causes.
How Is the Type Confirmed?
Your clinician will consider age, body weight, symptoms, family history, medicines, ketosis, speed of onset, and whether insulin was needed quickly. When the type remains uncertain, testing may include:
- Islet autoantibodies, usually GAD first and sometimes IA-2 or ZnT8
- C-peptide with a simultaneous glucose result to estimate insulin production
- Tests for pancreatic or genetic diabetes when the history is unusual
No single symptom or clinical feature confirms type 1 diabetes. C-peptide is interpreted carefully and is particularly useful when classification remains uncertain in someone receiving insulin.
How to Prepare for a Fasting Laboratory Test
- Have no caloric food or drink for at least eight hours.
- Plain water is allowed unless the laboratory gives different instructions.
- You do not need to avoid all carbohydrates at dinner merely to make the test look lower.
- Tell the clinician about steroids, illness, pregnancy, and medicines that may affect glucose.
Could Stress Explain the Result?
Stress, poor sleep, infection, and illness can raise glucose, but a confirmed fasting value in the diabetes range should not be dismissed as nervousness. It still requires timely evaluation.
Your fasting result of 197 mg/dL is also covered in our discussion of fasting glucose between 127 and 200 mg/dL.
When to Seek Urgent Care
Seek urgent medical care if high glucose occurs with vomiting, abdominal pain, deep or rapid breathing, fruity-smelling breath, severe dehydration, confusion, marked drowsiness, inability to drink, or moderate-to-large ketones. These can indicate diabetic ketoacidosis or another hyperglycemic emergency.
Also obtain prompt care for rapid unexplained weight loss, worsening weakness, or glucose rising toward or above 300 mg/dL.
What Should You Do Next?
- Confirm whether the unit was mmol/L or mg/dL and whether the result came from a laboratory or home meter.
- Arrange laboratory fasting plasma glucose and HbA1c testing promptly.
- Do not begin, stop, or borrow diabetes medicine before clinical assessment.
- If diabetes is confirmed, ask whether the clinical picture clearly indicates type 2 diabetes or whether antibody and C-peptide testing is appropriate.
What I want you to remember: fasting glucose of 8.6 mmol/L or 197 mg/dL is high enough to require prompt medical evaluation. The number can support a diabetes diagnosis when properly confirmed, but it cannot identify the diabetes type.
Written by: Dr. Albana Greca, MD, MMedSc, Family Physician
Medically reviewed by: Dr. Ruden Cakoni, MD, Endocrinologist
Last medically reviewed: August 4, 2026
Related Questions
- Is fasting blood sugar around 140 mg/dL high?
- Why is morning blood sugar higher than bedtime glucose?
Related Resources
- Blood tests used to diagnose diabetes
- Blood sugar ranges by test and time
- Fasting blood sugar from 127–200 mg/dL
References
- ADA Standards 2026: Diagnosis and Classification
- NIDDK: Diabetes and Prediabetes Tests
- CDC: Diabetes Testing
Educational safety note: General education only. Diagnosis and diabetes classification require laboratory testing and clinical assessment.
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