Similar to many of other diabetics, I have ongoing laboratory A1c blood tests prior to each scheduled Endo appointments. Could Dexcom Clarity software reporting present a key to compare my laboratory results as a tool for daily choices?

For many diabetics, both type1 (T1D) and type2, routinely have hemoglobin A1c (A1C) tests as part of their medical appointments. The thoughts and feelings of many T1D run the gambit. Feelings of fear, disgust, failure, shame and disappointment are only just a few due to the fact that A1C results are used to assess diabetes therapy. Have you ever chosen to not study and took an exam without any preparation for a final exam grade?  For many of us, this author included, exams can be a very challenging event. This raises the question. How can a T1D prepare for an A1C exam? What do we measure, when do we measure, how do we measure are all key questions?

Peter Drucker once said, “If you can’t measure it, you can’t improve it.” Let us look at changing the question facing a T1D. How can we take immediate actions during each and every day that could result in improved A1C results?

In January 2013, I launched the start of collecting and analyzing my continuous glucose readings with the start of a Personal Dexcom G4 Platinum continuous glucose monitor (PCGM). A YouTube, 3DviaT1D is a presentation of my startup and desires with the addition of a Dexcom unit. The next, challenge came with my 65th birthday. The fight with Medicare was over the best approach to manage my condition with my use of a PCGM unit

Using selected reports from Dexcom Studio software, reports were assembled to support the importance and value of using a PCGM. An article has appeared in the American Journal of Managed Care regarding my Medicare Appeal fight. Be sure to reference the pdf link to the complete article which contains five figures. After a twenty-four month period, the figures demonstrated that hypo and hyperglycemic events had been reduced. The objective of near normal blood glucose via A1C of 7.0% without the two to three fold increase in hypoglycemic events which was a major factor reported in the Diabetes Control and Complication Study.

Now, what can we assemble in ongoing reports from the new Dexcom Clarity software? The period reporting results which were chosen. They can be found in Table A. DEXCOM G4 Pt via DEXCOM Clarity Reporting.

A.   DEXCOM G4 Pt via DEXCOM Clarity Reporting
Average CGM
Date CGM Standard
Start End Range Estimated glucose Deviation
Date Date in days A1C mg/dL mg/dL
6/23/16 7/7/16 15 6.9% 152 61
7/8/16 7/22/16 15 6.4% 137 49
7/23/16 8/6/16 15 6.5% 139 46
8/7/16 8/21/16 15 6.6% 142 46
8/22/16 9/5/16 15 6.7% 147 51
9/6/16 9/20/16 15 6.6% 144 50
06/23/16 07/22/16 30 6.7% 145 56
07/23/16 08/21/16 30 6.5% 141 46
08/22/16 09/20/16 30 6.7% 145 51
06/23/16 08/06/16 45 6.6% 143 53
08/07/16 09/20/16 45 6.7% 144 49
06/23/16 07/22/16 30 6.7% 145 56
07/23/16 09/20/16 60 6.6% 143 48
06/23/16 09/20/16 90 6.6% 144 51
B.   Laboratory Results
Actual Glucose
Date   A1C mg/dL
9/20/16 blank 6.9% 151
C.   Comparative Results
9/6/16 9/20/16 15 6.6% 144 50
08/22/16 09/20/16 30 6.7% 145 51
08/07/16 09/20/16 45 6.7% 144 49
07/23/16 09/20/16 60 6.6% 143 48
06/23/16 09/20/16 90 6.6% 144 51
D. Comparative Accuracy Dexcom Est to Lab Actual A1c
% Ratio
Days Prior Est A1c to
to 9/20/16 Lab A1c
15 95.7%
30 97.1%
45 97.1%
60 95.7%
90 95.7%


There have been various comments regarding the accuracy and the time frame windows for A1C exam readings given the fact that an A1C reading is just one number as an average of blood glucose attached to a hemoglobin molecule. It is interesting to note that the data presented above for estimated A1C has a high correlation to the precise value obtained by the laboratory for A1C and Glucose level over various iterations of time frames.

How were the Dexcom Clarity Reports Assembled?

    1. The determined data range was adjusted and changed in the Overview Designation below your name.
    2. Next the report was produced and run from the Data Designation below your name.
  • Finally, a report was produced and run from the Compare Designation below your name.


  1. It was after receiving my A1C results from the laboratory, September 20, 2016, that the various time range reports were run and assembled into the matrix table listed above.

The ability does exist through the use of Dexcom Clarity to get a feel as to the range of one’s estimated A1C via their Dexcom reports prior to your A1C test. Table C, Comparative Results, listed above demonstrates a high correlation to the actual laboratory results. Anyone using a Dexcom unit, either G4 or G5 has the ability to view moving glucose levels. It is the small day to day adjustments which can bring about a change in results. How can we take actions to change the direction of the glucose flow direction as reported on our receiver unit or cell phone? One suggestion is to get a copy of Sugar Surfing by Dr. Stephen Ponder. Dr. Ponder is a pediatric endocrinologist and certified diabetes educator.

Table D, Comparative Accuracy Dexcom Est to Lab Actual A1c shows a high degree of accuracy of the Dexcom Est A1c to the Actual Laboratory A1c.

You may ask what can be done to improve the accuracy of your Clarity reports compared to your laboratory A1c results? Dexcom has prepared a “User’s Guide. Section 7.2 is How to Calibrate”. There are five bullet points, one Warning and one Precaution. There is another fact that we need to take into consideration. What is the accuracy of you particular blood glucose strips? This can be critical given the fact that we utilize a blood glucose reading every 12 hours. Using the extremes from Table D, an actual blood glucose meter reading of 100 mg/dL with a 10% accuracy factor computes to a range of 90 mg/dL to 110 mg/dL. A   blood glucose meter reading of 400 mg/dL with a 25% accuracy factor computes to a range of 300 mg/dL to 500 mg/dL.

Compare Actual Blood Glucose Reading to
the Range of Blood Glucose Reading adjusted for
Actual Range
Glucose Accuracy Low High
mg/dL Factor A – (A)x(B) A + (A)x(B)
100 10.0% 90 110
100 15.0% 85 115
100 20.0% 80 120
100 25.0% 75 125
200 10.0% 180 220
200 15.0% 170 230
200 20.0% 160 240
200 25.0% 150 250
300 10.0% 270 330
300 15.0% 255 345
300 20.0% 240 360
300 25.0% 225 375
400 10.0% 360 440
400 15.0% 340 460
400 20.0% 320 480
400 25.0% 300 500


As diabetics we need to take action with mechanical devises and directed actions to drive our glucose levels to a near normal ranges and reduce the roller coaster events for each and every day. You can check your daily results. Again, in Dexcom Clarity go to the Data Designation. Below your name and time frame title, on the far left are three choices. Click Daily. Now you have supporting documentation as to what is happening on a daily basis. Documented output facilitates discussions with health care professionals to determine optimal approaches.   It is the ongoing success of small changes repeated over time that can have the potential for better A1C exam results. Best of success in taking actions to prepare for your next A1C examination.