Is a capillary blood glucose (CBG) of 89 mg/dL normal and does it require any treatment?

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Capillary Blood Glucose of 89 mg/dL: Normal and Requires No Treatment

A capillary blood glucose (CBG) of 89 mg/dL is completely normal and requires no intervention. This value falls well within the normal physiological range and is not associated with any adverse outcomes.

Normal Glucose Ranges

  • Fasting capillary blood glucose of 89 mg/dL is within the normal range, which extends up to approximately 100-110 mg/dL depending on the reference standard used 1.
  • For non-diabetic individuals, mean fasting glucose values are typically around 83-92 mg/dL, with your value of 89 mg/dL falling squarely in this range 1.
  • The diagnostic threshold for impaired fasting glucose begins at 100 mg/dL (5.6 mmol/L) according to ADA criteria, or 110 mg/dL (6.1 mmol/L) according to WHO criteria—both well above your value 1.

Context for Diabetic Patients

Even if you have diabetes, a CBG of 89 mg/dL represents excellent glycemic control:

  • Preprandial (before meal) target range for adults with diabetes is 80-130 mg/dL, making 89 mg/dL an ideal premeal value 1.
  • This value is above the hypoglycemia threshold of 70 mg/dL, so there is no risk of low blood sugar 1, 2.
  • For pregnant women with preexisting diabetes, the recommended premeal glucose range is 60-99 mg/dL, and 89 mg/dL falls perfectly within this target 1.

No Treatment Needed

No action is required for a CBG of 89 mg/dL:

  • This value does not meet criteria for hypoglycemia (defined as <70 mg/dL), so no carbohydrate treatment is indicated 1, 2.
  • This value is not elevated, so no insulin or other glucose-lowering intervention is needed 1.
  • If this is a fasting value in someone without diabetes, it represents normal glucose metabolism and requires no follow-up 1.

When to Be Concerned

You should only be concerned about glucose values in the following situations:

  • Below 70 mg/dL: This meets the definition of hypoglycemia and requires treatment with 15-20 grams of oral glucose 1, 2.
  • Below 54 mg/dL: This represents clinically significant hypoglycemia requiring immediate treatment 1.
  • Above 126 mg/dL fasting or above 200 mg/dL random: These values suggest diabetes and warrant further evaluation 1.

Bottom Line

A CBG of 89 mg/dL is normal, healthy, and requires absolutely no treatment or concern. Continue your current management if you have diabetes, or simply maintain your current lifestyle if you do not have diabetes.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Immediate Treatment of Hypoglycemia

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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