Is being a Cyborg worthwhile? by Helen May
As well as my organic human parts, I also wear an insulin pump which compensate for my pancreas lacking some natural functions and a fitness monitor/watch which constantly measures my activity. As if that is not enough cyborgial gadgetry, I recently added a sensor to the mix to measure my blood glucose.
An alternative to finger pricking
As I mentioned in a previous post, I have started looking for an alternative to pricking my fingers to find out my blood glucose. The first foray into the automatic monitoring was the Freestyle Libre. This is a Flash Glucose Monitor rather than a Continuous Glucose Monitor (CGM). Although a Flash Monitor actually gathers Blood Glucose (BG) metrics all the time. Unlike a Continuous Monitor, the readings are only transmitted from the sensor to a reader when the sensor is “swiped”. As I am looking for an alternative to finger pricking and I have reasonable awareness, I am not too worried about proactively being alerted of too high or too low BG.
My first impression was surprise about how different the results were between the Libre and my usual finger prick readings. I understand that the Libre readings are less immediate than finger pricks – the Libre shows readings five minutes behind the finger prick. But these five minutes did not explain the scale of the differences (sometimes more than 2 mmol/l). I was told my body would take some time (up to 24 hours) to become comfortable with the Libre so, at first, I thought this was the reason for the difference. However, these differences continued.
Had my body trained itself?
Both the Libre and my usual meter have been approved so should be within the agreed standard. So I started to question my usual meter. Although I thought I was aware when I was starting a hypo (about 3mmol/l), I wondered if my body had trained itself to recognise feeling at this level. So I decided to research what is an approved level of accuracy. Since the end of May last year, meters need to meet these accuracy guidelines 95% of the time:
- Within ± 0.83 mmol/l of laboratory results at concentrations of under 5.6 mmol/l
- Within ± 15% of laboratory results at concentrations of 5.6 mmol/l or more
This means, meters can be wrong 5% of the time. It also means, the higher the reading, the less accurate it has to be. So if you compare two different meters on blood tested to be 15mmol/l (above the level ketones are likely to be present) in the laboratory, one meter could read as high as 17.2 and the other could be as low as 12.7. So, perhaps, I should be less surprised to see a difference of over 2mmol/l.
Trying to put these concerns to one side, I tried to stick with the Libre. Unfortunately, this was a bit of a problem as the Libre sensor did not want to stick to me. After three days, it fell off. Luckily, as part of the trial, I was entitled to one replacement sensor. And this time, I wrapped micropore tape around it to keep it on for its full 14 days.
My conclusion at the end of the trial was that £50 was a lot of money to spend every two weeks on something that I was not confident with the readings and was not confident it would stay in place. However, it was useful to see the profile of two weeks of CGM-type readings. I was able to make some adjustments on my pump especially around what happens whilst I am asleep.
How cyborg should I be?
A few weeks after I had decided against the Libre, I was at the gym taking a rest between exercises and checking my blood sugars with my traditional finger prick. A fellow gymmer approached me. He explained that he too had Type 1 diabetes and was a keen runner. He used the Libre all the time finding it great when he went out for a run with nothing but a packet of dextrose and his Libre receiver for company. This gave him the confidence to be in control. He too has spotted some odd readings but, as these were always in the higher range, they did not affect his ability to spot hypos which were far more likely when exercising. It was very interesting to get a different perspective.
Later this month, I have the chance to trial the Dexcom CGM. After that, armed with my experience of finger pricking, Flash Glucose Monitoring and Continuous Glucose Monitoring, along with the opinions from diabetes online fora (and fellow gymmers) as well as the price, I will decide how much of a cyborg I want to be.