Home blood prick tests - a waste of time?

JonW444

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A year ago I was diagnosed with prediabetes. I worked at losing weight, bought one of those small testing kits and it showed that I was out of the prediabetes zone. I tested myself every week or two for a year, sometimes after food, sometimes first thing in the morning, sometimes any time of day. All results for the year were lower than 7mol/L, some in the low 4's, most mid 5's, a few 6's. I felt happy that things were going OK.

So, a few weeks ago I had a few blood tests ordered by my GP , one was blood sugar levels, and it came out as being HbA1 of 42 - prediabetes! I don't see how all tests for the year can be wrong unless the kit is effectively useless!?! It's pretty disappointing.

Are the home test kits just a waste of time?
 
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The finger prick test gives you a read of your blood glucose at a single point in time - naturally, this varies according to your food intake and activity.
The GP HbA1c test is a measure of your average blood glucose over the previous 12 weeks so tends to be a better marker of your blood glucose.

Don't be disheartened - Your GP test result will be a picture of the previous 12 weeks. You know how to get your HbA1c down so maybe try those approaches to food and exercise again and request a GP re-test in 12 weeks :)
 

Lamont D

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First of all, 42 is on the brink of prediabetes.
An hba1c test is for you BG levels for the previous couple of months. It is a different test than finger prictest.

It is not a waste of time!
Doing random tests, is just that random.
If you can do a fasting test before breakfast is useful.
Give yourself fifteen minutes to half an hour after getting up. Try and be as regular with the test.

Then there is testing around meals, pre meal and two hours after.
This will tell you, what your diet is doing to your BG levels.
If you get a reading below 2 mmols higher than the pre meal reading then something in that meal, is spiking your BG levels too high. If it is below 2mmols higher, that meal is okay.
This will help in discovering which foods are producing the higher spikes.

Have you altered your carb and sugars intake to help with getting your hba1c levels down?
 

JonW444

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Thanks for the replies, but I still don't get how anyone can think that those home finger prick tests are any use at all if their results never reflect your true state? I can understand that they are just that one moment in time, but if they, over a year of time and at varying times of day etc NEVER reflect your true condition then there is no point in them at all. I'm frustrated!
 
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Melgar

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A year ago I was diagnosed with prediabetes. I worked at losing weight, bought one of those small testing kits and it showed that I was out of the prediabetes zone. I tested myself every week or two for a year, sometimes after food, sometimes first thing in the morning, sometimes any time of day. All results for the year were lower than 7mol/L, some in the low 4's, most mid 5's, a few 6's. I felt happy that things were going OK.

So, a few weeks ago I had a few blood tests ordered by my GP , one was blood sugar levels, and it came out as being HbA1 of 42 - prediabetes! I don't see how all tests for the year can be wrong unless the kit is effectively useless!?! It's pretty disappointing.

Are the home test kits just a waste of time?
@JonW444 , I usually use a Continuous Glucose Monitor (CGM) which records your blood sugars continuously by measuring your blood sugars in your interstitial fluids. I also have a Contour Next One glucometer. I can tell you that both read low. My preference, without a doubt, is the cgm. You can see real time what your blood sugars are doing at any given moment, at any time of day. The glucometer requires a more structured approached to testing your blood. Usually first thing in the morning, your fasting blood sugars; when you first take a bite of your meals and two hours after. And if you want last thing at night. What they do not show you is how your body is coping with your over all carb intake. Sure you can see if your blood sugars are rising over a period of time if you are recoding your results. That is it. Useful in tha fact that if your blood sugars are way up there, you will know it from your finger prick test. It is not meant to predict your Ac1's. The cgm attempts to give you an estimated Ac1, but in my experience, it always underestimates Ac1 results. The only sure way to know your Ac1's is an Ac1 test.

 
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ianf0ster

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Hi @JonW444 and welcome to the forum.

So, you have found out that the tests aren't 100% accurate. This also applies to the HbA1C test as well which is shy for many diagnosed with T2 Diabetes it requires 2 HbA1C tests of 48 or more.

What did you expect? Did your GP lead you to believe that a single finger prick test at a random time of day was a meaningful predictor of your HbA1C. Given that the allowed accuracy of the BG meters id +- 15%, that would be incredible.

In my experience, the best use of a BG meter for a Type 2 is in getting their way of eating correct so that they can gain T2D remission. The reason I say that is because it was true for me. I found my fasting BG level was always quite high and varied unpredictably because of Dawn Phenomenon. Sure, the trend was very slowly downward on my Low Carb way of eating, but even after gaining remission my DP pushed my BG up so it was often the highest measurement of the day and it took my first meal of the day to reduce it. That was just my liver being used to higher BG levels and being 'helpful' in giving me the energy to go hunt/gather my breakfast!
 

jjraak

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Thanks for the replies, but I still don't get how anyone can think that those home finger prick tests are any use at all if their results never reflect your true state? I can understand that they are just that one moment in time, but if they, over a year of time and at varying times of day etc NEVER reflect your true condition then there is no point in them at all. I'm frustrated!
Mmhh.

So random tests, You say .

Be as useful as sticking you finger out of the window and predicting the week's weather, imho.

BG is dynamic, it's influenced by so many variables....exercise, stress, mood, etc etc

As a scientific experiment, random is pointless without the recorded data of the above plus likely a dozen other points of reference to make any sense of it.


HBA1c is the designated standard for testing that BG level scientifically.

It is just ONE test to judge where we are each year or there abouts.

It's the destination or waypoint, if you like, of our annual journey once DX'd.

The pin pricking is really designed to help show us the ONE thing that seems to be agreed to increase or decrease our bgs level at set times and thus our HBA1c over time.

And THAT one thing IS Food, specifically CARBOHYDRATES

Pin pricking isn't meant to be ONE test PROOF, like the HBA1C is

Pin pricking is our Google maps to get us as safely as possible to a better HBA1c number, than just trusting & hoping we're doing *IT right....
(*Whatever diet or program we're using or were told to use to help lower our HBA1c)

And as such, it's used to measure DIFFERENCES & TRENDS

The difference between food we CAN tolerate better
Versus the foods we tolerate less well.
Thus guiding us to better good choices

And the trend we initiate by modifying out WOE & lifestyle, which those food choices help us dictate.

Which all links rather nicely with the Pre meal & post meal testing regime

And also gives an indication if our overall trend is downwards using our FBG levels each morning.

Not all encompassing, but a very useful guide, which I and many others have used to lower our HBA1c & lowering the risk of complications further down the road.

Useless ...?

Not in my experience.

I'd say it's an essential for guiding any T2D's journey from DX to lowering their HBA1c.

For those interested, a good read of the forum helps but a simple idea, is our bodies are chock full of glucose at dx, we're literally a pot of glucose spilling over ........Every - Single - Meal... :banghead:

The entire idea IS to limit the glucose input, and in doing so, the excess glucose has a chance of being used up, which is why the FBG is the last number to tumble for many.

Best of luck on your journey.
 
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Melgar

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Slightly going off piste with this, but there is also a growing body of research that suggests blood sugar spikes , and I am using spike as a term because researchers use that term for differentiating a rise above base line and overall patterns, are actually significant signifiers as to how your body is actually coping with your meal. Yes, for sure if your blood sugars preprandial are at 6mmol/ls then 2 hours after your meal they are around 7.5 mmol/ls, you might be happy with that and think your body has coped well with your meal, but in fact, it hasn’t. What it hasn’t shown you is that your blood sugars rose to 12.5 mmol/ls came down a bit to 10.5 and stayed there for chunk of the time and came down just before the 2 hour mark, following a second phase insulin release. What it doesn’t tell you is what your first phase insulin release is doing. If it’s happening at all. If I used my finger prick test before and after a meal I would not know how high and for how long my blood sugars stayed up and, significantly that I have in fact lost my first phase insulin release and my sugars don’t go up until nearly 45 - 60 mins later and stay up for longer than they should, they form a plateau and are not pointy.
 

Outlier

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The most useful thing for me was being able to check what affected my BG in any given circumstance. As we are all individual in our responses, I found what was useful for me, rather than having no more information than how my BG had been overall over an extended time. I learned how my own Dawn Phenomenon worked, how exercise affected my BG, likewise outside circumstances such as rage, fear, frustration, minor infections, pain etc etc. It's about a whole lot more than food. This weaponised my knowledge and gave me the thrust to keep going because if my BG did rise, I knew why. In my case, the fingerprick tests are far more valuable than the HbA1c, which doesn't take into account what else was going on in my life over the timespan.
 

KennyA

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A year ago I was diagnosed with prediabetes. I worked at losing weight, bought one of those small testing kits and it showed that I was out of the prediabetes zone. I tested myself every week or two for a year, sometimes after food, sometimes first thing in the morning, sometimes any time of day. All results for the year were lower than 7mol/L, some in the low 4's, most mid 5's, a few 6's. I felt happy that things were going OK.

So, a few weeks ago I had a few blood tests ordered by my GP , one was blood sugar levels, and it came out as being HbA1 of 42 - prediabetes! I don't see how all tests for the year can be wrong unless the kit is effectively useless!?! It's pretty disappointing.

Are the home test kits just a waste of time?
It all depends how you use them. My experience is that I needed a structured rather than random pattern of testing. I found that testing immediately before food and then at +2 hours was extremely useful in enabling me to work out which foods (and illness, and exercise, and stress) did what to my blood glucose. Yes, there is an expected level of inaccuracy (as there is for the A1c) but it evens out.

As the A1c and the fingerprick tests are testing different things - the A1c counts glycated red blood cells, which is a useful proxy for BG levels over the last three months or so, and fingerprick tests give you a BG reading at that instant, you might expect some difference, and it seems clear from many experiences that one cannot be reliably predicted from the other.

So your fingerprick test results were not necessarily wrong: they may have been perfectly accurate in themselves. But tests every week or two, at different times etc. won't show a pattern. Yes, you might catch a very high reading, by chance. But you have no idea what was happening to your BG when you weren't testing. The conclusion drawn from the test values might not therefore have been the correct one.
 
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jpscloud

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I find fingerprick tests useful for a couple of reasons - firstly it keeps me motivated to stay off carbs, as I can see an immediate high response in BG when I eat them (I still do eat carbs sometimes, just not all the time as I used to) and secondly I can see trends over time.

The fingerprick tests in my case usually show slightly higher than my HbA1c results, but the trends are the same. Maybe it's a bit like weighing yourself every day - it's rarely going to be a linear result either for loss, gain or maintain, but a weekly average and monthly trends are very useful indicators of how you're doing.

It depends how much you want to see of what's going on, I suppose. Testing for specific foods is educational and can be motivational but at the end of the day, if you stay off carbs (including the hidden ones) you will have good results overall.
 
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In Response

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Resurgam

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@JonW444 That is rather like being disappointed that, despite testing the tire pressure, the car still gets punctures.
I have a scientific education and working background, so I set about determining the amount of carbs to eat as a series of experiments, and the numbers on the test meter were used for comparison of before and after levels rather than actual numbers set in stone.
Once I knew the sort of levels and timing to aim for, I didn't need to test other than once in a while to see how things were progressing.
 

ajbod

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The Hba1c is a bit like the speeding ticket that drops through the letterbox. The finger prick test is the glance at the speedometer, you may only see 30 mph when glancing, but at some point you were travelling faster, but didn't see it.
Random testing is useless, and a waste of strips. You need a proper system to actually know what is going on.
 

oldminer88

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Just had a Free style Libre for 15 days found useful to see what different foods and exercise affect my pre-diabetes. Readings seem to go a bit haywire towards end. Finger prick tests were always lower. Was 47 h1ac 6 months ago managed to get into normal range with low carb diet , exercise after every meal and 15 hr fasting
 

LivingLightly

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Good evening @JonW444 and welcome to the forum.

You cannot extrapolate from finger prick blood glucose tests or CGM readings to HbA1c results, because they measure different things.

If you perform a random finger prick test, the result depends largely on when you last ate, so provides limited information.

The most important time to test IMO is just before you take the first mouthful, be it breakfast, lunch or dinner. Then compare that first reading with the result two hours later. The second reading should be no more than 2 mmols/l above the first one and no higher than 8 mmols/l.

If you can achieve that consistently (by adjusting your carbohydate intake where necessary), your FBG levels first thing in the morning should gradually fall, but those are often the last to come down.
 

Roy Batty

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I found little correlation between finger prick results and HbA1c. I tried testing several times at 3 a.m. to eliminate the dawn phoemenom. Most testing was between 7 and 7.30 a.m. after waking aned before eating or drinking anything. For months I saw no meaningful change, almost always between 6 and 6.5. HbA1c tests showed a reduction in my blood sugar. The pre and post (within 2 hours of eating) prandial tests never showed an increase >2. I stopped finger prick testing, it wasn't useful.
 

Omar51

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I have been taking finger tests for about 15 years now. 8-10 hours of FBG, mostly first thing in the morning. Randomly before and 2 hours meals. I keep records and it works well for me. I am pre and I don’t take any medication.
 
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Lainie71

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The term "big boned" lol repeatedly told this growing up!
Its never a waste of time, I still test and it varies everyday dp is very unhelpful but it is what it is. Testing is a good habit to have for me ;)
 
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Lupf

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Hi @JonW444 welcome to the forum.

Please you shouldn't despair. Let me try to explain what these measurements are
Finger pricks measure your current blood sugar (BS) level.
HbA1c measures an average over three months of glycated haemoglobin, which is glucose attached to your red blood cells.
These two measurements are not measuring the same things.
These days GPs only use HbA1c to define if you have diabetes > 48 or prediabetes between 42 and 48.

Your BS measurements are actually quite good, but they have a 15% accuracy and variations between batches of strips have been observed.
Thus you should not over-interpret these and as you found out if you use a conversion table, e.g. 6.0 corresponds to 37,
but your HbA1c came back as 42, which BTW also has an uncertainty of 6%, so it could actually be 40 or 44.

In my view finger pricks are useful, as you can observe patterns over time,
e.g. BS is going up or down, but measuring at random times might not be the best strategy.
Very useful is measuring before and 2 hours after a meal as this gives you information on how well you tolerate different foods.
I started measuring always after getting up, so being in the same condition.

As mentioned by others there are CGMs which measure your BS continously, but by yet another method,
so again the absolute values need to used with care.
 
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