Blood Glucose Monitoring Frequency with 70/30 Insulin
If you are taking 70/30 insulin (Novolin 70/30), you should check your blood glucose at least 4 times per day: before breakfast, before dinner, at bedtime, and when you suspect low blood sugar. 1
Recommended Testing Schedule
Minimum Daily Testing Points
- Before breakfast (fasting) - to assess overnight glucose control and guide morning dose adjustments 1
- Before dinner - to evaluate daytime glucose control and guide evening dose adjustments 1
- At bedtime - to prevent nocturnal hypoglycemia, which is a particular risk with premixed insulins 1
- When you suspect low blood sugar - premixed insulins like 70/30 carry significant hypoglycemia risk 2, 3
Additional Testing Situations
- After treating low blood sugar - continue testing until glucose normalizes 1
- Before exercise - to prevent exercise-induced hypoglycemia 1
- Before critical tasks like driving - to ensure safety 1
Why This Frequency Matters
The American Diabetes Association specifically recommends that people using multiple daily insulin injections perform blood glucose monitoring at least 4 times daily, as this frequency has been strongly associated with better glycemic control (lower A1C levels) across all age groups 1. Testing less than 3-4 times daily in insulin-treated patients has been linked to worse glucose control 1.
With 70/30 insulin specifically, frequent monitoring is even more critical because this premixed formulation contains both intermediate-acting (NPH) and short-acting (regular) insulin components, creating multiple peak action times throughout the day when hypoglycemia risk is highest 4, 2.
Key Monitoring Targets
- Fasting glucose goal: 90-130 mg/dL 1, 2
- Peak postprandial glucose: <180 mg/dL 1
- Adjust your evening dose if more than 50% of fasting readings are above target 2
- Reduce your dose by 2 units if you have more than 2 low readings per week 2
Critical Safety Considerations
Common Pitfalls to Avoid
- Never skip bedtime testing - nocturnal hypoglycemia is particularly common with 70/30 insulin due to the NPH component's overnight action 1, 5
- Don't rely solely on fasting glucose - you need pre-dinner readings to properly adjust your morning dose 2, 3
- Maintain consistent meal timing - 70/30 insulin requires eating 30 minutes after injection, and skipping or delaying meals significantly increases hypoglycemia risk 2, 3
When to Test More Frequently
During dose adjustments or regimen changes, you should monitor even more frequently - the guidelines recommend evaluation every 2 weeks with adjustments as needed 2. If you're experiencing frequent hypoglycemia or your glucose control is unstable, increase testing frequency beyond the minimum 4 times daily 1.
Why Not Less Frequent Testing?
Studies demonstrate that testing fewer than 4 times daily in insulin-treated patients results in higher A1C levels and increased risk of both severe hyperglycemia and undetected hypoglycemia 1. The fixed 70/30 ratio provides less flexibility than separate basal-bolus regimens, making frequent monitoring essential to detect patterns and prevent complications 2, 3.