BC ADM Blood Glucose Monitoring 2 — Questions and Answers
Question 1: A patient's CGM shows a rapid rate-of-change arrow pointing straight down (>-3 mg/dL/min). What is the most appropriate immediate action?
- Recheck with fingerstick and treat hypoglycemia proactively (Correct answer)
- Wait 15 minutes and recheck CGM
- Administer correction insulin dose
- Increase basal rate on insulin pump
Correct answer: Recheck with fingerstick and treat hypoglycemia proactively
A rapid downward trend indicates fast-falling glucose requiring fingerstick confirmation and proactive hypoglycemia treatment before symptoms develop.
Question 2: Which factor most commonly causes falsely elevated SMBG readings in patients using older glucose meter technology?
- Hypotension
- Maltose or xylose interference with glucose oxidase strips (Correct answer)
- Hypothyroidism
- High altitude exposure
Correct answer: Maltose or xylose interference with glucose oxidase strips
Maltose (found in icodextrin peritoneal dialysis solutions) and xylose can cause falsely elevated readings with glucose oxidase-based test strips.
Question 3: For a patient with T1D using a hybrid closed-loop system, when should fingerstick BG be used instead of relying solely on CGM values?
- Every 4 hours during the day
- When symptoms don't match CGM reading or before treating severe hypoglycemia (Correct answer)
- Only during exercise
- Once daily at fasting
Correct answer: When symptoms don't match CGM reading or before treating severe hypoglycemia
Fingerstick verification is essential when symptoms are discordant with CGM values or before treating severe hypoglycemia to ensure clinical safety.
Question 4: What is the recommended minimum number of daily SMBG checks for a patient with T1D using multiple daily injections (MDI) who is NOT using CGM?
- 2 times per day
- 4 times per day
- 6–8 times per day (Correct answer)
- Once per day at fasting
Correct answer: 6–8 times per day
ADA standards recommend at least 6–8 SMBG checks daily for T1D patients on MDI to guide insulin dosing decisions at meals, bedtime, and overnight.
Question 5: A patient's CGM time-in-range (TIR) is 58% with 12% time below range (TBR). Which adjustment should be prioritized?
- Increase mealtime insulin to improve TIR
- Address hypoglycemia (TBR) before attempting to improve TIR (Correct answer)
- Start a new CGM sensor immediately
- Increase basal insulin dose
Correct answer: Address hypoglycemia (TBR) before attempting to improve TIR
Hypoglycemia (TBR >4%) must be addressed first as it poses immediate safety risk and may paradoxically be worsening TIR through hypoglycemia-driven rebound hyperglycemia.
Question 6: Which CGM metric best captures glycemic variability independent of mean glucose level?
- Time in Range (TIR)
- Coefficient of Variation (CV) (Correct answer)
- GMI (Glucose Management Indicator)
- Mean Amplitude of Glycemic Excursions (MAGE)
Correct answer: Coefficient of Variation (CV)
Coefficient of Variation (CV) expresses standard deviation as a percentage of mean glucose, allowing comparison of variability across different mean glucose levels.
Question 7: A patient reports their CGM readings are consistently 25–30 mg/dL higher than simultaneous fingerstick values. What is the most likely explanation?
- The patient is in ketoacidosis
- Interstitial-to-blood glucose lag during rapidly rising glucose (Correct answer)
- The CGM sensor has expired
- The patient is using acetaminophen
Correct answer: Interstitial-to-blood glucose lag during rapidly rising glucose
CGM measures interstitial glucose, which lags behind blood glucose by 5–15 minutes during rapid rises, causing CGM to read higher when glucose is actively rising.
BC ADM Blood Glucose Monitoring 2
A patient's CGM shows a rapid rate-of-change arrow pointing straight down (>-3 mg/dL/min).
What is the most appropriate immediate action?