When should a diabetic patient recheck their blood sugar levels?

When to Recheck Blood Sugar Levels in Diabetic Patients

For diabetic patients with stable glycemic control meeting treatment goals, recheck A1C every 6 months (twice yearly), but increase to quarterly (every 3 months) for those not meeting goals or with recent therapy changes. 1

A1C Testing Schedule

Stable Patients Meeting Goals

• Check A1C at least twice yearly (every 6 months) for patients who are meeting treatment goals and have stable glycemic control 1, 2
• This applies to patients with type 2 diabetes who have stable glycemia well within target 1

Unstable Patients or Those Not Meeting Goals

• Check A1C quarterly (every 3 months) for patients whose therapy has recently changed or who are not meeting glycemic goals 1, 3
• This interval allows sufficient time for medication titration, dose optimization, and assessment of patient adherence and lifestyle modifications 3
• Highly intensively managed patients (such as pregnant women with type 1 diabetes) may require testing more frequently than every 3 months 1

Daily Blood Glucose Monitoring Frequency

Patients on Intensive Insulin Regimens

• Check blood glucose 6-10 times daily for patients on multiple-dose insulin or insulin pump therapy 1, 3
• Specific timing includes: before all meals and snacks, occasionally after meals (postprandially), at bedtime, before exercise, when suspecting hypoglycemia, after treating low blood glucose until normoglycemic, and before critical tasks such as driving 1, 3
• The American Diabetes Association emphasizes that increased daily self-monitoring frequency is significantly associated with lower A1C (0.2% per additional test per day) and fewer acute complications 1

Patients Not on Intensive Insulin

• Monitor blood glucose when appropriate based on therapy, which may include checking when fasting, prior to meals, after meals, at bedtime, when hyperglycemia or hypoglycemia is suspected, and during medication or lifestyle adjustments 1
• For non-insulin-treated patients, monitoring frequency should be individualized but is particularly helpful when modifying meal plans, physical activity, or medications that can cause hypoglycemia 1

Postprandial (After-Meal) Glucose Monitoring

Optimal Timing

• Check postprandial glucose 1-2 hours after the beginning of the meal, as this generally captures peak levels in patients with diabetes 1
• Research shows the mean peak time after meals is approximately 72 minutes (about 1 hour and 15 minutes), with 80% of post-meal blood glucose peaks occurring within 90 minutes of starting the meal 4

When to Target Postprandial Glucose

• Target postprandial glucose if A1C goals are not met despite reaching preprandial (before-meal) glucose goals 1
• This is particularly important because postprandial hyperglycemia is very common—84% of non-insulin-treated type 2 diabetic patients have at least one postprandial glucose reading >160 mg/dL (8.9 mmol/L), even among those with apparently good metabolic control 5

Special Monitoring Situations

Hypoglycemia Risk

• Check glucose immediately when hypoglycemia is suspected, and recheck after treatment until normoglycemic 1
• Patients at risk for hypoglycemia should be screened for impaired hypoglycemia awareness at least yearly 1
• All individuals treated with insulin or at high risk of hypoglycemia should have glucagon prescribed and monitoring plans in place 1

Continuous Glucose Monitoring (CGM)

• Consider early initiation of CGM, including at diagnosis, depending on patient needs and preferences 1
• CGM serves an important role in assessing treatment effectiveness and safety, particularly for preventing hypoglycemia in type 1 diabetes and in selected type 2 patients on intensive insulin regimens 1
• Patients using CGM must still have access to blood glucose meters at all times for calibration and confirmation 1

Important Caveats

A1C Limitations

• Conditions affecting red blood cell turnover (hemolytic anemia, G6PD deficiency, recent blood transfusion, end-stage kidney disease, pregnancy) may cause discrepancies between A1C and true mean glycemia 1
• Hemoglobin variants should be considered when A1C results don't correlate with CGM or self-monitoring readings 1

Meter Accuracy

• Only use FDA-approved glucose meters with unexpired test strips purchased from pharmacies or licensed distributors and properly stored 1
• Avoid purchasing or using preowned or secondhand test strips, as these may give incorrect results 1
• Evaluate each patient's monitoring technique initially and at regular intervals to ensure accuracy 1

Correlation Between Measurements

• Fasting plasma glucose is a poor indicator of glucose at other times of day, with correlation coefficients ranging only from 0.50-0.70 6, 7
• The correlation between fasting glucose and A1C is not very strong (r = 0.73), and for the same fasting glucose value, A1C can vary markedly 6, 7