How I test my Blood Glucose

How I test my Blood Glucose

Understanding the impact that food, exercise and stress have on my Blood Glucose is at the heart of managing my Type 2 Diabetes; this post explains how I do it.



"BG - Blood Glucose

"Blood Glucose" - the amount of of glucose (sugar) in my blood, measured either as mmol/L (the international standard and is most common measurement used in the UK) or mg/dL (used predominantly in the USA and continental Europe)

A high” - when my BG is higher than I would like or am comfortable with At the time of writing my target is to always keep my BG at or below 8 mmol/L, and I would consider a high to be anything over 10 mmol/L

Hyperglycemia” - a clinical term for high BG, defined by the World Health organisation as greater than 7.0 mmol/L when fasting or greater than 11.0 mmol/L 2 hours after a meal

a BG spike” - a short term or quick rise in my BG

Why I test my Blood Glucose

Despite the title of this post, after I had written 80% of it I realised that the best way to start was to talk about why I test my Blood Glucose (BG), so here we go; outside of illness and infection, the cause of high BG is the food I eat, and carbohydrates in particular. I tried to find a simple explanation of carbohydrates to link to here, but unsurprisingly anything that was not extremely nerdy came with a complement of dietary advice that was either without any scientific basis or something I strongly disagree with. You will just have to take a look at this dictionary definition, and do some more reading if you are interested in learning more.

Unlike someone using external insulin to manage their BG, when mine rises above the range I endeavour to keep it in there are not many options; practically it is only exercise that will bring it down to a more desirable level. Going for a brisk walk or a swim is not always practical or something I feel like doing, so a lot of the effort I put into managing my Type 2 Diabetes (T2D) goes into learn from the experience and try to do things differently in the future.

When my Doctor sends me for a blood test to check on my progress in managing my T2D, it is usually a Glycated Haemoglobin test, commonly known as an HbA1c test. This gives an indication of my average blood glucose levels over the previous two to three months, although it is heavily weighted towards the  previous 10 days or so. Whilst this may be a useful measure of my overall progress, it gives no insight into what I am doing well, and what I am doing badly. To understand what is happening on a day to day, or more importantly meal to meal basis, I use one of the modern generation of Self-Monitoring of Blood Glucose (SMBG) meters. These are small enough to carry around in my pocket or bag and provide a near instantaneous reading of my current Blood Glucose level.


How I test my Blood Glucose (the practical bit)

What I am going to describe in the following paragraphs is an accumulation of advice from others and my practical experience in the last few years. However, by far the largest contributor to my understanding of this subject is a blog by my friend Mike

He in turn extensively quotes from "Jennifer's Advice", a widely circulated note of very practical advice of uncertain origin. I don’t know who Jennifer is, but it’s well worth a read on Mike’s site, as the many other excellent articles by him, Jane, Ellen and Beth.

I use an Accu-Chek® Aviva Blood Glucose Meter. I didn’t choose this, but it was the one available in the nearest pharmacy shortly after I was diagnosed and decided it was something I needed. There is a useful video from Diabetes UK  that shows how a meter like this used


When I test my Blood Glucose (the philosophical bit)

My meter and the test strips it uses are expensive and I pay for all of them myself; this is a result of current UK guidelines which I strongly believe are misguided and based on faulty science. I have written about this elsewhere, and I won't go over the same ground again, but you are welcome to read more about it in this post.

Who ever foots the bill for my testing , I feel I need to use them wisely and avoid testing out of habit. This means that I test in one of two circumstances;

  1. If I can believe that I will learn something from testing (by far the most frequent)
  2. If I believe I am in danger of hypoglycemia (low-BG) and I could be a danger  to myself or others (very infrequent)

With this in mind, as time goes on I typically test less and less over time; as I better understand the impact of my daily life and diet (both of which can be pretty repetitive). These days my testing is more frequently when I am traveling, eating new foods (or combinations of food), under particular stress or when I am training very hard.


When I test my Blood Glucose (the timing bit)

My first test of the day, and my most frequent test, is as soon as practical after waking (usually this is after I have found my glasses, fed the cat and have put the kettle on). This test is analogous to a fasting BG test that some doctors use and it gives me a good indication of how how good my control was the previous day, and particularly if my dinner choices were good. I also find it useful as an early indication of coming illness or infection.

Les frequently I test my BG after a meal; when I first started to do this I tested 2 hours after a meal (as recommended by many sources), but as I have learnt to achieve better control over by BG I more typically test 1 hour after a meal, with the aim of achieving a reading of not more than 8 mmol/l.


What I do with the test results

I take the results of my testing, together with my food diary and exercise records, and try to figure out what works (i.e. doesn’t cause a spike in my BG) and what does not. At first this seemed like trying to complete a complex jigsaw puzzle whilst blindfolded and wearing heavy gloves, but as time has gone on a picture has gradually emerged and the small individual lessons learnt have built into a reasonable understanding of how my daily life, the food I eat and stress I am under all interact to affect my BG control. That is not to say that things are always smooth going; my body’s reaction to all of these factors is surprisingly varied.

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