Monitoring Techniques Flashcards

A patient's HbA1c is 6.8% but her CGM data shows frequent hypoglycemic episodes. What phenomenon explains this discordance?

Answer: Glucose variability with high/low averaging

Alternating hyperglycemic and hypoglycemic episodes can average to a deceptively 'normal' HbA1c while masking dangerous glycemic variability.

Which CGM metric best quantifies the degree of glucose fluctuation beyond the average level?

Answer: Coefficient of variation (CV)

Coefficient of variation (CV) measures glucose variability as a percentage of the mean; a CV ≤36% is generally considered stable.

A continuous glucose monitor sensor placed on the abdomen shows a consistent 20–30 minute lag behind fingerstick values during rapid glucose changes. This is because:

Answer: CGM measures interstitial fluid glucose, which lags behind blood glucose

CGM sensors measure glucose in interstitial fluid, which equilibrates with blood glucose with a physiological lag of approximately 5–15 minutes that is amplified during rapid changes.

What is the recommended blood ketone (beta-hydroxybutyrate) threshold that should prompt a patient to seek emergency care?

Answer: ≥3.0 mmol/L

Blood ketone levels ≥3.0 mmol/L indicate high DKA risk and warrant immediate emergency evaluation.

A structured SMBG pattern shows consistently elevated glucose readings 2 hours after dinner but not after breakfast or lunch. What is the most appropriate clinical response?

Answer: Evaluate and modify the evening meal composition and/or pre-dinner medication

Pattern management directs intervention to the specific meal and corresponding medication or dietary factors causing the postprandial spike.

Which type of glucose meter is MOST appropriate for a patient with sickle cell trait whose readings have been unreliable?

Answer: A meter validated for hemoglobin variants and abnormal hematocrit ranges

Hemoglobin variants and hematocrit abnormalities can interfere with some meters; selecting one validated for these conditions improves accuracy.

During sick-day management, how frequently should a patient with type 1 diabetes check blood or urine ketones?

Answer: Every 4–6 hours or whenever glucose exceeds 240 mg/dL

Sick-day rules recommend checking ketones every 4–6 hours or with each high glucose reading above 240 mg/dL to detect DKA early.