CGM Vs. FGM Vs. Fingerstick

Muslim Kapasi showing FGM Flash glucose monitoring system and CGM continuous glucose monitoring system

If you are wondering what these abbreviations are, allow me. I am here comparing three blood glucose-monitoring systems; this is my take on the ones currently available in India and by no means is influenced or biased since I paid for all of them myself from my own hard earned money. 😉 Besides, I also went a bit haywire with my food and schedule intentionally to see how the readings moved with various systems.

The three that I am comparing here are Medtronic’s Enlite, Abbott’s Freestyle Libre Pro and Accu-Chek Active. My idea of writing this blog is not to get too technical since sufficient reference material is now easily available online, so please search for the terms or write a comment below and I will be more than happy to explain. However, for the basics of understanding the three vary as follows.

Medtronic’s Enlite is a real-time Continuous Glucose Monitoring (CGM) system, it takes an interstitial reading every 5 minutes and transfers it through a transmitter attached to the sensor to the insulin pump and shows a real-time value plus graph of how blood sugars are moving. The insulin pump could even action a low glucose suspend or warn when the blood sugars are moving too rapidly in either direction. CGM systems also need to be calibrated at least once every 12 hours, so the fingerstick reading isn’t eliminated completely yet.

pic 3Abbott Libre Pro is a Flash Glucose Monitoring (FGM) system, it takes an interstitial reading every 15 minutes and you need a flash reader to read the blood glucose. Requires no calibration so no need to prick the fingers anymore, just flash the reader and voila! unfortunately Abbott has only made available the Pro version in India, for which you need to go to the Doctor every time to download the entire trend, all readings at a go. So, the finger pricking needs to still continue here or at least until Abbott launches the consumer version (FreeStyle Libre, no Pro) in the market. Also, this is an independent system that does not crosstalk with insulin pumps, at least not yet.

pic 4test bloodAccu-Chek Active (Fingerstick) is the conventional system where we take a small blood sample mostly by pricking our finger tips on to a strip inserted in the Glucometer for a spot reading. Now most of us are acquainted with this as we have been using this at rhymes home since decades already so I will spare you from more details.

I usually check my blood glucose using the Fingerstick method at least 6 times a day- fasting, before lunch, postprandial, before exercise, before dinner and at bedtime. For ease of comparison, I am going to take it at an average of 7 pricks a day! (I know, its probably more often than I drink water.)

Diving straight into my experiences as a user of all 3 systems simultaneously, here we go… but if this bores you at anytime please feel free to jump straight to the conclusion at the bottom. :)

price riseAs Indians, one of the most important criteria is value for money since we as ‘people with diabetes’ despite paying higher premiums do not get any insurance reimbursements, appropriate tax write-offs or government funding/incentive to manage our health better using the latestgraph 1 new and best technologies available
to us from across the world. Of the three systems and depending on the Fingersticks done each day, it still is the Fingerstick method that might seem more economical to use but this isn’t an apple-to-apple comparison.

We are comparing say 7 readings with Fingerstick method to 96 readings with FGM to 288 readings with CGM a day. (Though I have many a times been able to extend the CGM to work beyond its prescribed 6 days, sometimes even able to stretch it beyond 14 days.) 

graph 2 newA far cry I would say, in the number of readings, although 288 readings a day might seem a bit too many unless it has a specific purpose to it, I would be quite happy with the 96 readings since it then keeps the current FGM device active and accurate for 14 days instead of the official 6 days with CGM. Again the number of readings viz. 1728 on CGM is still much higher than 1344 on FGM through the life of both sensors.

graph 3 newTalking about number of days, Libre was affixed on my triceps (arm, as it has only been passed/recommended to be fixed on the arm currently) stayed on quite relentlessly for all 14 days and beyond despite of me testing it thoroughly in the Gym and with multiple showers on Gym days too.

pic 5aFor me, the skin around it had turned itchy from 7th day onwards. I have sensitive skin so don’t take this to heart, I checked with a few friends who too had tried the Libre and they did not have any similar issues. Enlite, however, had to be reinforced with multiple overtapes to keep it in place on my Abs, which still failed on the 9th day.

pic 6 croppedA fun experience in the Gym was that since the Libre was visible on my arm, other people in the Gym enquired what it was and a few even wanted it as they thought it looked quite cool. Although the Enlite remains hidden under the vest (it can be fixed on triceps/arms or anywhere you may think it works best for you) and my experience with it the previous times too, training the body part where the sensor was fixed threw the readings out of order or the sensor failed.

Now for the accuracy, which is the most critical part. There is still no contest between a reading taken from blood glucose and interstitial fluid as I noticed some lags in both CGM and FGM readings. The readings taken through interstitial fluid which surrounds the cells of the tissue below the skin, and usually glucose moves from blood vessels and capillaries first and then into the interstitial fluid so the reading from Fingerstick will always be ahead. Although I was quite impressed with the results I was getting from the Libre Pro, being more accurate and with a shorter lag as compared to Enlite.

Irony is that the readings from interstitial fuilds across different parts of the body vary and that is where I feel that some benefit of doubt goes in favour of Libre. pic 7It is known that the insulin absorption is most rapid into the abdomen followed by arms, then the legs and finally the buttocks. And the sequence and speed of blood flowing to these regions vary as well.

Ease of applicability and pain, Libre takes the cake here, as there was virtually no pain. I did not even feel or remember a sensor was sticking to my arm unless it drew some attention. 😉 And fixing it was a breeze too. In comparison the Enlite that takes around 10 minutes of careful application to two hours of warm up before it starts picking the trend, the Libre starts giving the readings after one hour of quick fixing.

medtronicAlthough, the most unfair part here is that the CGM was real-time and I could see the readings all the time on my insulin pump but since the Libre Pro’s reader was only with the doctor and unless I ran to the doctor every 15 minutes for a reading (I’m not joking), I was perceivably blind for the entire period this was on my body.

Insulin pump could also take notes of the meals, activities, fingersticks, insulin doses, etc. and shows full analytics using the Medtronic software. Whereas for the Libre Pro, it had to be manually noted (either on paper or third-party Apps) and painstakingly correlated with the sensor glucose trend instead.

pic 8I am lucky to have a doctor and friend who sits across to discuss the graphs and suggests corrections to my basal sets but I have heard of many horror stories where people with diabetes did fix the Libre Pro and then downloaded the results after 15 days to barely even get a proper 10 minutes discussion of any value from the results, which is deterring to say that many first time users might also be last time users.

pic 12 full (2) pic 12 full (1)

Though each has its own advantages and disadvantages at this stage, I think there will be better devices and better solutions coming soon.hand smilie fingers I am also a big believer of economies of scale making newer and better technologies cheaper and more accessible over time and hence the device of preference here ought to be the FGM since it eradicates the need of pricks completely and the number of readings being more than enough for daily consumption in comparison to the CGM or painful pricks otherwise making the fingers sore.

In a few years from now, and unless a cure for diabetes is available, I don’t think that people will really need to prick their fingers as a reader in the smartphone or wristwatch communicating with an almost invisible sensor affixed somewhere on the body will constantly tell us our blood glucose readings, carbs consumed, activities done, etc. altogether with insightful analytics… let’s hope its fewer than a few years!

Click the images/pictures to enlarge them.

 

38 Comments on this article

  • Beemajan August 8, 2016
    You are a legend. I am using libre freestyle flash monitoring. 20 times and adjust my dose food etc I can read it instantly no need of any doctors I do trial and error method. Sometimes in deep sleep of I dream of something unpleasant my reading is high. My insulin dosage has come down but the sensor is expensive 10000 rupees a month. Every Fortnight a sensor

    Reply

    • MuslimKapasi August 9, 2016
      Thank you so much, Beema. I don't think the bulkiest of majority in India would use sensors all the time or even once a year, not yet. Even the penetration of Glucometers is still a fraction of the total diagnosed diabetic population in India despite them being given away free by manufacturers now. There is no price for health or there is!

      Reply

      • Sajan January 13, 2017
        Sir I have just started now to use Abott Libre pro device and connected with my phone via Glimp application to check the reading after every 15 minutes . Here the confusion is my glucose meter shows 205 whereas abott shows 153 stable. Approx the difference of 50 to 60 points coming with every comparison. Should I consider reading of abott or glucose meter? My glucose meter is one touch select which gives a quite accurate reading.

        Reply

        • MuslimKapasi January 13, 2017
          Hi Sajan, Please check your Glucometer again, it may need calibration. Alternately use a different Glucometer to verify or take a few readings at the local chemist or your Doctor. The variation from Libre and Fingerstick is always there but not as large as 50 to 60 mg/dl, besides always factor the lag. I always tell people on CGMS or FGMS to treat the trend and not the number as that can always vary from time of the day to where you are in your food digestion or activity cycle. All the best!

          Reply

  • Namrata Dhanak August 8, 2016
    Brilliant analysis! You've covered all the practical points.

    Reply

    • MuslimKapasi August 9, 2016
      Thanks Namrata. Hope we get a lot more time or at least how much we deserve to discuss our graphs/trends next time onwards. The wonderful work you did analysing your own FGM results should be used by the Abbott programming team to incorporate an analysis software within the reader itself.

      Reply

  • andimaus August 8, 2016
    Hi Muslim I read nearly everything. First your information for the CGM is not the latest one. Withe transmitter g you can do more then only reading. The CGM works now activ with the pump "Guardian" I will not go into to much details but The pump can stop before you are low already the pump stops "before going into low " to safe you - I think you should go ahead and make the comparision with latest version possible as the had been great changes. The other systems to my knowledge do not work together with the insulin pump so the results can not be obtained -- and a pro version is nice but nothing to help at the spot. According the costs you get what yoy pay for.

    Reply

  • andimaus August 8, 2016
    a watch testing blood sugar existed was taken from the market short time later -inaccurate The pump with cgm cost like a car but far from being one Excuses are medical equipment need time .... Compared the development in the sector to others like cancer /aids there is nearly no move so I am pessimistic about the not necessary fingerprick in some years from now.

    Reply

    • MuslimKapasi August 10, 2016
      I am aware of the watch, inhalers and other devices that didn't make it to the market. When Glucometers were first developed and launched, they were the size of a 20 inch CRT television, would often fail, give grossly inaccurate readings and would take an hour to show the reading... but thats how tools, technologies, solutions evolve and converge, isn't it?

      Reply

  • andimaus August 8, 2016
    you can never compare plasma and capillary blood -- there are even meters working with different methods and results and it is know that the plasma results have a time lack of about 10 min.- but this is not the main thing - interesting is the trend where does to have a curve and knowing if your blood sugar come from up or runs down - to have the advantage of not having a point information -

    Reply

  • andimaus August 8, 2016
    about the costs /insurance : would you pay insurance fees every month of about 20% of your salary to get reimbursement ? easy to say you do not get reimbursement

    Reply

    • MuslimKapasi August 10, 2016
      Sorry Andrea, if you are not happy with my comparative analysis but this is from my own first hand experience using all three systems simultaneously and I did discuss plus evaluate it with Doctors, T1Ds and T2Ds (all from India) who had used these systems before to then come up with this blogpost. There is no one opinion that can be absolutely right but I try my best to support it with facts. We can always agree to disagree... thank you so much for your feedbacks as always.

      Reply

  • Angad Chandhok August 8, 2016
    Great stuff. This actually broadened my horizon ! :)

    Reply

  • Mutton August 9, 2016
    Hey Muslim,,, Pretty interesting comparison and detailed as well to give someone a decent background of what to choose from! Personally, i have only used the CGM so far, and have been disappointed 2/3 times that i used it simply for the reason, that it does not stay well on the abdomen. And since i do rigorous workouts, it'd not stay properly where its supposed to causing errors in readings or come to a stage where it'd have to be removed entirely. Doc's and CGM personnel's say that "you shouldn't do such activities when on the CGMS"- then what would the entire purpose be of getting a CGMS when all i am going to do is just sit?! The FGM has a relatively safer positioning considering the movement and flexibility of that region. And its difficult to not keep looking at the pump while on a CGM. Its cool and all to see the graph go up and down, but its affects you mentally when you see sugars rise and fall, with the amount of activity and active insulin in your body,, and all the more so because its LAG reading. You start doubting your own senses and judgement/ bodily signs in such cases. Finger stick is an all timer. And I can do 8-10 pricks in a day when needed to make sure i am on the right path. And that path can be cross checked and rectified more accurately with these 2 devices. All that said- being the "Diabetic Capital of The World"- its high time medicines and other tools and facilities for better health care are made available more easily and economically,

    Reply

    • MuslimKapasi August 10, 2016
      Thanks Harsh. :) Fantastic point there- what would be the entire purpose of a CGMS if it limits you with doing things that are important for your health, case in point is not able to exercise when applied. Another very good point is that the pump connected to the CGMS beeping and forcing an obsession into you to keep checking the sensor glucose levels and to manage them first.. quite annoying I agree! Though the new generation CGMS should solve these issues and integrate better with the pump, but I would not siege to trust my own senses and judgements to manage my health better...

      Reply

  • Jhanviv August 9, 2016
    This is really helpful, my son is a T1 and hope to read more from you for help!

    Reply

  • pragya August 9, 2016
    That's simply superb comparison.. Exactly what I was looking for at this time when I was considering FGM for my 8 year old type1 son. Would be interested to know how much is the difference in the readings at same point of time with all the three glucose monitoring methods, if there is any. I follow your blogs and have learned a lot!!! Thanks so much...looking forward to the next one!!!

    Reply

    • MuslimKapasi August 11, 2016
      Thank you so much, Pragya-ji. :) Any suggestions for the next one, any particular topics of concern that you think needs to be covered?

      Reply

  • anirudh August 9, 2016
    Thank you,sir.incredibly informative and helpful.

    Reply

  • Ana August 10, 2016
    Great post. My experience with these devices is similar and we also struggle with insurance and have to fight tooth and nail to have somewhat limited access to technology and "modern" treatment. My best from Argentina!

    Reply

  • PRASHANTH mani August 10, 2016
    Wow. What an article. Unbiased and gives clear understanding of all the systems. You are doing a tremendous job in making us gain information on health care. I don't want to use pumps. So will procure freestyle from outside India. The libre patch fell from my arm after I banged it couple of times, I re-attached it and it worked.

    Reply

  • Zainab patanwala August 10, 2016
    Wow muslim , thats more than any diabetes educator can compile.. I have just finished my course on diabetes recently but let me say i hav practical training with you people right here on this forum.

    Reply

    • MuslimKapasi August 11, 2016
      Thanks Zainab, I am glad that you are able to benefit from this website. We need more health care professionals who are both empathic and cued in. Welcome to the fraternity, we are all very "sweet" people! :)

      Reply

  • Anup sharma August 10, 2016
    cgms results will come after 15 days. Meanwhile we maintain a very exhaustive diary where timings of everything we do including bath, eating, taking insulin/medicines drinking water, thinking good thoughts/ worrying, feeling guilty, anxious, fearful, lethargic, active, sleepy, all different feelings of the body like itches, discomforts, comforts, feeling relaxed, happy etc etc. Is noted and checked for its reaction on blood sugar. Hoping to find some connections that release insulin from sleeping beta cells

    Reply

    • MuslimKapasi August 11, 2016
      There are Apps that can record all details as you mentioned but to correlate it all with the blood sugar movements in the charts is a huge issue and a painstaking process. Waking up the sleeping islet on langerhans or beta cells is a cure, soon I hope & pray! :)

      Reply

  • Anup sharma August 10, 2016
    awesome work done by u muslim.

    Reply

  • Monali Shah August 11, 2016
    A very exhaustive and frank comparison.. (user oriented and not a biased company oriented..) The point that I want tp still know more about since I have never used a CGM or even an FGM is that were u able to compare the precise readings at a particular moment and not the approximate timings. If yes, then how close were they? When anything is done meticulously, the results are bound to bring a positive and welcome change in one's life and I hv managed doing it to the point with the old-fashioned Fingerstick method. So now there's a tiff between my wallet n the ease in diabetes management,.. So whom to side more..?

    Reply

    • MuslimKapasi August 11, 2016
      Dear Monali, Thank you for reading this article and I am glad you found it useful. :) I did compare the readings and they weren't synchronising to say the least unless when the blood sugars were steady flat for 30 minutes minimum. Most of the times they were showing a consistent pattern but during workouts they were far apart and sometimes during meals they even went a bit wary. I have uploaded all graphs with their timings for you to see as well, fingerstick readings start from 7 am instead of midnight so align accordingly. You will notice that one chart has slightly more emphasised highs & lows versus the other. Health is Wealth.. you decide whom to side more!

      Reply

  • Faiziya Soomar September 6, 2016
    Thanks, this was highly informative. My daughter, a t1d uses contour glucometer.we have limited ourselves to this way of tracking bg levels, as our doctor hasn't told us about the other options.

    Reply

    • MuslimKapasi September 22, 2016
      Thank you for reading and following my blog. Now you can ask the Doctor about these devices but remember, it is the person and the equipment can only be as good as the person who manages her diabetes. All the best!

      Reply

  • Riddhi September 21, 2016
    Wow Muslim Such comparisions Requires Patience Time Money n dedication U hv proved it all Dis is so useful for us I hv just started with abbot n actually wondering is dis gonna b useful as wo a reader its of no use Practically after eating n taking insulin It wud b great to see ur sugars going in wht direction or range n dat wud help to note down our actions n d reactions N a reader will help a lot Wo a reader d data after 14 days wudnt b of Great help

    Reply

    • MuslimKapasi September 22, 2016
      Thanks Riddhi for reading the article. The version you are referring to is called Libre (without the Pro), that one hasn't been launched in India yet. However, an active Sensor can be read using a mobile phone with Near Field Communications (NFC) and the Gimp or an App written using Tidepool platform, there are quite a few now floating around for free download on the internet. You being on the Pump already could have instead opted for the Enlite CGMs and that would have given you realtime information in sync with the doses and the carbs you eat, so taking corrective steps could have been easier and faster though. Libre Pro will give you a day to day analysis/trends of your blood glucose movements, I suggest you note down everything as there are countless things that affect blood sugars and then compare to the graphs and make corrections subsequently, then try another session on Libre Pro to verify the changes/corrections. All the best!

      Reply

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