YDC Product Troubleshooting Guide : 012 - CGM ACCURACY

Problem

Patient needs assistance with CGM Accuracy

If off-label insertion site is indicated, remind the patient of the approved site(s) and that if placed in other areas, the Dexcom System may not function properly. Document this education in the Discussion/Resolution section.

Questions to be asked

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Questions to be documented

012.1 Has a Blood Glucose Meter reading been taken for comparison?

012.2 What is the sensor reading and BG value at the time of inaccuracy?

012.2.1 Did the patient experience any symptoms prior to and/or at the time of the event?
012.2.2 Was there any treatment provided to alleviate symptoms prior to and/or at the time of the event?

012.2.2.1 If yes, what specifically was the treatment provided and by whom?

012.2.3 What is the patient’s current condition?

012.3 Was the BG value confirmed with a second measurement within a 5-minute period?

012.4 Have there been similar inaccuracies with this sensor session?

012.5 Prior to noticing the difference between CGM and BG, were calibrations entered?

012.6 Did you calibrate the CGM after you noticed the difference?

012.6.1 Did the calibration bring the CGM reading into the expected range?

012.7 Prior to the event, did any of the following occur that could contribute to a discrepancy between the CGM and BG values?

012.8 Did the patient take medication containing acetaminophen (paracetamol)?

012.8.1 If yes, document the dosage, frequency, and time of last dose prior to the inaccuracy.

012.9 Did the patient take Hydroxyurea?

012.9.1 If yes, please document the dosage, frequency, and time of last dose prior to the inaccuracy.

012.10 G7/D1+ Only: Did issue occur during the 12-hour grace period?

Actions

1. Document Yes or No or Unable/Unwilling to answer. If Yes - continue to 012.2 If No or Unable/Unwilling to answer - continue to 012.4
2. Document the answer. Put the values into the OSC Inaccuracy Calculator. If outside the range, proceed with troubleshooting. Additionally, if BG values are below 40 mg/dl (2.2 mmol/L) or above 400 mg/dl (22.2 mmol/L), continue to 012.2.1 (NOTE: Your CGM may differ from your BG measurement. If your CGM readings differ from your symptoms or expectations, you should perform a BG measurement and if that value more closely aligns with your symptoms, use that BG value for your diabetes management decisions. If the BG value and CGM are different, it is helpful to repeat a fingerstick. If PT states that the CGM system shows values below 40 mg/dl (2.2 mmol/L) as LOW or above 400 mg/dl (22.2 mmol/L) as HIGH, educate the range of CGM.
       2.1 Please document in patients own words, in chronological order.
       2.2 Document Yes or No or Unable/Unwilling to answer. If Yes – continue to 012.2.2.1 If No or Unable/Unwilling to answer – continue to 012.2.3
          2.2.1 Please document in patients own words, in chronological order. (NOTE: This field contains all the treatment and medications provided to the PT prior to and/or at the time of the event (oral, IV, topical, inhaled etc.) medical procedures, and who gave the treatment.)
       2.3 Please document in patients own words, in chronological order.
3. Document Yes or No or Unable/Unwilling to answer.
4. Document Yes or No or Unable/Unwilling to answer.
5. Document Yes or No or Unable/Unwilling to answer. (NOTE: Calibrations bring your CGM value closer to your BG meter value.)
6. Document Yes or No or Unable/Unwilling to answer. If Yes – continue to 012.6.1 If No or Unable/Unwilling to answer – continue to 012.7
      6.1 Document Yes or No or Unable/Unwilling to answer.
7. Record all the answers that apply to this question.
8. Document Yes or No or Unable/Unwilling to answer. If yes – continue to 012.8.1. If No or Unable/Unwilling to answer – continue to 012.9; G6/D1 is contraindicated for amounts over 1,000 mg over the course of 6 hours. Acetaminophen (paracetamol) can falsely elevate CGM readings. The length of time that acetaminophen (paracetamol) affects the system's performance is based on dose and length of time since dose.
9. Document all usage and frequency of drug, even if the dosage is small. Document Yes or No or Unable/Unwilling to answer. If Yes – continue to 012.9.1 If No or Unable/Unwilling to answer – continue to 012.10 If PT using G7/D1+ (NOTE: The length of time that Hydroxyurea affects the system’s performance is based on dosage and length of time since dose. Hydroxyurea is a medication used in sickle-cell disease and cancer treatment. It’s also known as “Hydroxycarbamide”.)
10. G7/D1+ Only: If yes, please advise that it is recommended to change the sensor when the session expires at 10 days. The grace period can be utilized when the end time is not convenient for the user. No replacement product will be provided for issues during the grace period. Please document the complaint.

Images

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Reasons behind

This can be normal, and the sensor can be inaccurate for several reasons: the sensor may have shifted, was not able to accurately track a rapid rise or fall, a contraindication was encountered, or the sensor was just not performing to specs (off 3 times in a 24-hour period, despite extra calibration attempts).  This is a sensor issue.