Is a fasting blood sugar of 89 normal?
Yes. A fasting blood sugar of 89 mg/dL (4.9 mmol/L) is normal. Normal is under 100 after 8 hours with no food, the same line at every adult age.
NormalPrediabetes rangeDiabetes range
What it means
Fasting means 8 hours or more with no calories, water only. Under 100 mg/dL (5.6 mmol/L) is normal, 100 to 125 (5.6 to 6.9) is the prediabetes range, and 126 (7.0) or more is the diabetes range. 89 sits 11 points under the prediabetes line.
Can this number decide it?
Only a lab test decides a band, and a diagnosis takes two results unless the number is clearly high. A finger-stick meter or a sensor can't diagnose, and a sensor runs higher than your blood.
What to do
Nothing to do for this number. Test every 3 years from age 35, sooner if your weight goes up, and yearly once a number lands in the prediabetes range.
When to get help now
Call 911 or go to the ER if a blood sugar stays at 300 or more, or comes with vomiting so you can't keep fluids down, fruity breath or hard breathing. Under 70 with confusion, fainting or trouble swallowing is an emergency too. Pregnancy uses tighter numbers, so take any number to your midwife or doctor, and if you take insulin or a sulfonylurea, your targets come from your prescriber.
