CDE Monitoring Techniques 4 — Questions and Answers
Question 1: A pregnant woman with type 1 diabetes asks about CGM use during pregnancy. What is the recommended glucose target range for pregnant women using CGM?
- 70–180 mg/dL for >70% of the time
- 63–140 mg/dL for >70% of the time (Correct answer)
- 80–160 mg/dL for >75% of the time
- 70–140 mg/dL for >60% of the time
Correct answer: 63–140 mg/dL for >70% of the time
ADA recommends a tighter CGM target of 63–140 mg/dL for >70% TIR during pregnancy to optimize fetal outcomes.
Question 2: Which site is generally associated with the SLOWEST glucose absorption, making it least reliable for detecting rapid glucose changes?
- Fingertip (capillary bed)
- Forearm (alternate site) (Correct answer)
- Upper arm
- Thigh
Correct answer: Forearm (alternate site)
Alternate sites such as the forearm have slower capillary glucose equilibration and are unreliable for detecting rapidly changing glucose values.
Question 3: A glucometer displays an 'HI' reading instead of a numerical value. This typically indicates blood glucose is:
- Above the meter's upper measurement limit (usually >600 mg/dL) (Correct answer)
- A calibration error requiring a new strip
- Hemolysis in the blood sample
- A communication error with the lancing device
Correct answer: Above the meter's upper measurement limit (usually >600 mg/dL)
'HI' indicates the glucose exceeds the meter's upper measurement limit, typically >600 mg/dL, and requires immediate clinical evaluation.
Question 4: What is the primary limitation of the Ambulatory Glucose Profile (AGP) report for clinical decision-making?
- It only displays fasting glucose data
- It requires at least 14 days of CGM data and does not reflect acute changes in therapy (Correct answer)
- It cannot be generated from CGM data
- It measures HbA1c rather than glucose
Correct answer: It requires at least 14 days of CGM data and does not reflect acute changes in therapy
AGP requires at least 14 days of CGM data to generate a representative 24-hour glucose pattern and reflects past rather than current management.
Question 5: A patient reports that her CGM repeatedly alarms for hypoglycemia at night but fingerstick readings taken at the alarm show 90–100 mg/dL. The MOST likely explanation is:
- The CGM alarm threshold is set too high
- Interstitial glucose lags behind blood glucose during nocturnal glucose recovery (Correct answer)
- The CGM sensor has expired
- The fingerstick meter is reading falsely high
Correct answer: Interstitial glucose lags behind blood glucose during nocturnal glucose recovery
During nocturnal glucose recovery from a low, interstitial glucose lags behind the rising blood glucose, causing the CGM to still read low when blood glucose has already recovered.
Question 6: Which coding system for blood glucose meters was eliminated in the US to reduce user error?
- ISO 15197 coding
- Strip lot coding via a code chip or manual entry (Correct answer)
- Factory calibration coding
- QC coding for control solutions
Correct answer: Strip lot coding via a code chip or manual entry
Strip lot coding (entering a code for each new vial of strips) was a major source of error; most US meters now use factory calibration to eliminate this step.
Question 7: What does 'glycemic variability' measurement add beyond HbA1c in assessing diabetes management quality?
- It measures average glucose more accurately than HbA1c
- It identifies the magnitude and frequency of glucose excursions that increase oxidative stress and cardiovascular risk (Correct answer)
- It quantifies insulin resistance independently of glucose
- It replaces the need for SMBG in type 2 diabetes
Correct answer: It identifies the magnitude and frequency of glucose excursions that increase oxidative stress and cardiovascular risk
Glycemic variability captures glucose swings that contribute to oxidative stress, hypoglycemia risk, and cardiovascular outcomes beyond what the average reflected by HbA1c reveals.
CDE Monitoring Techniques 4
A pregnant woman with type 1 diabetes asks about CGM use during pregnancy.
What is the recommended glucose target range for pregnant women using CGM?