Fasting plasma glucose, any point for long term Type 1s?

[Robin]

Is there absolutely no point in this test for an established Type 1, or have I lost the plot?

Had my bloods done yesterday, surgery was on the phone this morning saying, 'The doctor wants to repeat your blood plasma test' Asked if she was sure, as there wasn’t much point to this test in a Type 1 who had been juggling their insulin to avoid going hypo while waiting for a fasting bloods test. Obvs, she didn’t know, and she didn’t have a result for it. (I didn’t have one last year, and the one in 2017 was the first for 5years)

So I agreed to be retested tomorrow morning, in case I’ve missed something, but really, can anyone see a point to it?

When I have a fasting test, I have to lower my basal the night before just in case I hypo in the night, and then I trot down to the surgery with my Dawn Phenomenon in full swing. I gave myself a cautious two units of insulin to counteract it (the surgery is only 100 yards down the road) but nearly got caught out, as I had to wait 20 mins for the appointment. (Was still in the 6s on the Libre, though, while I was at the surgery). I can’t blame the nurse for running late, she was ministering to an elderly gent who looked like he had face-planted into something solid, but this also adds to the Roulette Wheel of Glucose for us Type 1s.

Got my HbA1c results from yesterday, they were online already, 48, exactly the same as last year. I'll take that . (incidentally, the Libre was predicting 42, but the Libre average will always include those parts of the night where I was squishing the sensor and read falsely low)

 

[Bruce Stephens]

So I agreed to be retested tomorrow morning, in case I’ve missed something, but really, can anyone see a point to it?

I don't know of any. I assumed it was just one of the boxes my GP marks off when I have a fasting blood test, but that the result was of no particular consequence. Normally you want waking BG to be in range (not too low, not too high), but for a proper blood test (where you'll have to travel a bit, and can't eat) even that's a bit optimistic, IMHO.

I wonder why your doctor wanted to repeat it?

 

[everydayupsanddowns]

The only check I thought gave more reliable results as fasting was the full lipid panel.

Might be worth asking GP the reason for the check, and what they believe it will tell them?

Congrats on your 48 by the way. Cracking result!

 

[Bruce Stephens]

The only check I thought gave more reliable results as fasting was the full lipid panel.

Presumably fasting plasma glucose is a different thing to plasma glucose (especially for T1); it just doesn't seem likely to be a clinically interesting difference for someone that's T1. (My twice-yearly blood tests are fasting presumably because they include full lipid panel.)

I wonder if it's just some tickbox thing: that there's some guideline that the test ought normally to be over 5.0mmol/L and you weren't, or something? (Or maybe there was some problem and they couldn't produce a number, and rather than just dropping it (since this value's probably not clinically useful anyway) your doctor asked for a repeat.)

 

[Robin]

Thanks guys.
The only reason I could think of why it would tell you anything, was that if I had a good HbA1c, but my fasting glucose was in the teens, or in the twos, it might tell a GP that my glucose management was more chaotic than it appears.
Looking at my results on line, though, there doesn’t seem to be one for Plasma Glucose, it says N/A, so I suspect it was an automatic tick box thing, and the lab dropped the test tube or something. I will discuss it with my GP, but my old GP has just retired, and I’ve got to break in a new one, so wanted to be sure of my facts!

 

[TheClockworkDodo]

I've never had a fasting test of any sort done in nearly 10 years of diabetes, and no-one has ever suggested to me that I should.
So if you're missing something, I'm missing it too!

 

[Bruce Stephens]

I've never had a fasting test of any sort done in nearly 10 years of diabetes, and no-one has ever suggested to me that I should.

Not even for lipids? It may depend on area. I think in some places they just do overall cholesterol levels. Maybe there are methods that do OK without fasting, too. (The blood plasma glucose thing is just BG, so a fasting one's useful for someone who's not T1 diabetic.)

 

[Robin]

The only check I thought gave more reliable results as fasting was the full lipid panel.

Might be worth asking GP the reason for the check, and what they believe it will tell them?

Congrats on your 48 by the way. Cracking result!

Turns out it was human error, aided and abetted by the computer. Nurse had pressed the button to order the test, then not sent a sample off for it, so it flagged up as 'sample missing'. The upshot was that yes, I did need to go in and have it, ‘because it was on the list'. It seems it’s easier to extract blood from my arm than extract an unnecessary blood test from The System!

It did give me the opportunity to have a chinwag with the senior admin/nurse who I’ve known for years, about all the teething problems they’re having with admin changes now they’re giving the surgery a shake up! In future, my annual review will be around my birthday. I protested this was grossly unfair as it’s just after Christmas, and she said, don’t worry, come in for your blood tests in December!

 

[Bruce Stephens]

The upshot was that yes, I did need to go in and have it, ‘because it was on the list'. It seems it’s easier to extract blood from my arm than extract an unnecessary blood test from The System!

Quite likely the whole thing was pretty much automatic, then. Likely if you talked to your GP they'd be able to remove it (and would be fine doing so, since I doubt it has any clinical significance). But maybe it's not so easy, I guess. Sometimes these things take on a life of their own and it can be much easier just to go along with it.

 

[Robin]

Quite likely the whole thing was pretty much automatic, then. Likely if you talked to your GP they'd be able to remove it (and would be fine doing so, since I doubt it has any clinical significance). But maybe it's not so easy, I guess. Sometimes these things take on a life of their own and it can be much easier just to go along with it.

The only plus point was, I did a test with my blood glucose meter at the same time, and swiped my Libre at 3 minute intervals afterwards, so it’ll be useful to compare those against a proper lab test.

 

[Ralph-YK]

I never have fasting blood tests, at all, ever. I've had a number of Hab1c, along with various other blood tests. T2.

 

[Robin]

I never have fasting blood tests, at all, ever. I've had a number of Hab1c, along with various other blood tests. T2.

I once asked the hospital consultant about fasting for Cholesterol tests, because the hospital didn’t ask for fasting ones, and our GP surgery did!
He said, they never used to ask Diabetic patients to fast, because of the difficulty of avoiding a hypo, in the days when people were generally on twice daily mixed insulins.
He said now that people were generally on MDI, and had more control, he reckoned that if they could manage a fasting one, the results would be more accurate. (I think it’s often the Triglycerides that are affected by having eaten).
You don’t need to fast for an HbA1c, or any of the other myriad of tests I seem to have.

 

[everydayupsanddowns]

Ha! Glad you managed to get to the bottom of it. Admin and system changes in surgery computers are fraught with challenges!

 

[Ralph-YK]

I once asked the hospital consultant about fasting for Cholesterol tests, because the hospital didn’t ask for fasting ones, and our GP surgery did!
He said, they never used to ask Diabetic patients to fast, because of the difficulty of avoiding a hypo, in the days when people were generally on twice daily mixed insulins.

I was giving a T2 non insulin users perspective. Don't know if there's a difference between types here. Or insulin users.

 

[Ljc]

I once asked the hospital consultant about fasting for Cholesterol tests, because the hospital didn’t ask for fasting ones, and our GP surgery did!
He said, they never used to ask Diabetic patients to fast, because of the difficulty of avoiding a hypo, in the days when people were generally on twice daily mixed insulins.
He said now that people were generally on MDI, and had more control, he reckoned that if they could manage a fasting one, the results would be more accurate. (I think it’s often the Triglycerides that are affected by having eaten).
You don’t need to fast for an HbA1c, or any of the other myriad of tests I seem to have.

That’s my understanding too.

 

[TheClockworkDodo]

Not even for lipids? It may depend on area. I think in some places they just do overall cholesterol levels. Maybe there are methods that do OK without fasting, too. (The blood plasma glucose thing is just BG, so a fasting one's useful for someone who's not T1 diabetic.)

Not for anything. I usually have my blood tests at 4pm, I'm in bed in the mornings.

 

[Robin]

Well! My plasma glucose result was online today. 7.1. Not that tells anyone anything, but the interesting thing was, I did a glucose meter test and a Libre swipe at the same time, just to see how they compared, and ........
They were both also 7.1!
OK, the Libre went up to 8 ten minutes later, and back down to 6.5 ten minutes after that, but, I don’t know what the odds are on all three being the same figure at the same time!

 

[leonS]

I believe that NHS guidelines state that no type 1 diabetic should be asked to take a fasting blood test as the information can be obtained in other ways.

BUT I could not find the reference for this last night.