Type 2 Fasting before blood tests

[Flora123]

Does it matter how long you fast? I know there is a minimum, but is there a maximum?

Edited to add - Also, annual checks are due and it says cholesterol non fasting. Is there a reason for that? I’m having some Medichecks done at the same time which do need to be fasting. Will that muck up the NHS ones? I know the Medichecks ones will be more in depth. Thanks

 

[bulkbiker]

Depends on the blood tests.. for cholesterol 12-14 hours is considered ideal.. shorter doesn't clean out the last meal enough and longer can start to switch on fat burning so may increase the cholesterol levels in the blood.

 

[Flora123]

Thanks @bulkbiker. I hadn’t realised the actual reasons.

 

[Flora123]

Why do the NHS not do a fasting cholesterol? Is it because it’s not a full test?

 

[Tophat1900]

Why do the NHS not do a fasting cholesterol? Is it because it’s not a full test?

If they are not doing a full lipid panel then it's pointless doing it imo.

 

[bulkbiker]

Why do the NHS not do a fasting cholesterol? Is it because it’s not a full test?

Not sure what you mean? I always fast pre cholesterol blood draws then request a full lipid profile. If you haven;t fasted they usually won't do it as its pretty meaningless.

 

[Flora123]

Not sure what you mean? I always fast pre cholesterol blood draws then request a full lipid profile. If you haven;t fasted they usually won't do it as its pretty meaningless.

I can request it from the ones the doc has sent me for hence I do Medichecks myself. It’s a pity they don’t do it.

 

[HSSS]

Fantastic timing. Have tests tomorrow. Though my medichecks ones still haven’t shown up, ordered last wed! Hoping they are here in the morning before I leave

 

[Member496333]

I have an annual review coming up in a couple of weeks and I haven’t been asked to fast, even though I know full well that they will be testing cholesterol. Just as well I couldn’t give a monkey’s about it. I’ll pay for a full lipid panel if I ever have cause for concern. Cholesterol testing is the biggest con in the past hundred years. In my opinion only of course.

 

[HSSS]

Out of interest the medichecks info says fasting for insulin resistance 8-10 hrs and for cholesterol seems best at 12-14hrs. Any idea why the difference? I understand for cholesterol it drops noticibly after 12 hrs but is the 10hr max for insulin for convenience or other reasons.

Unless the test kit finally shows up in the morning it’s by the by though, as my nhs phlebotomist agreed to do it with my 3 month tests tomorrow and if it’s not here then it’ll have to wait til next time frustratingly.

 

[pavlosn]

What is an insulin resistance test please. I dont believe I ever had one. Is this the same as a glucose tolerance test or something different.

Thank and spologies if I am diverting slightly.

 

[Mr_Pot]

Why do the NHS not do a fasting cholesterol? Is it because it’s not a full test?

I think the reason is because most people will want to fast by delaying their breakfast. This results in everyone requesting appointments early in the morning and causing a bottleneck. Hopefully anyone with a particularly high cholesterol will get a second, more detailed, fasting test. I fast anyway and ask for the full lipid breakdown.

 

[Member496333]

What is an insulin resistance test please. I dont believe I ever had one. Is this the same as a glucose tolerance test or something different.

Thank and spologies if I am diverting slightly.

Commonly HOMA-IR. Homeostatic Model Assessment of Insulin Resistance. In itself it is not a test. It’s a calculation using a formula. It uses two variables - fasting glucose and fasting insulin - to calculate a ratio of insulin resistance. The idea is to see how much insulin is being used in order to achieve the given measured glucose level. A ratio of 1.0 or below is considered normal (not much insulin required to achieve normal glucose). Above 1.0 is considered to be on the spectrum of resistance (too much insulin required to achieve normal or higher than normal glucose).

 

[pavlosn]

Thank you for the explanation.

Although I routinely have a fasting glucose test done whenever I have a blood test, i only remember my doctor requesting a fasting insulin test once on first diagnosis ten years ago.

I dont remember what the result was other than it was high.

I am going to the same medical lab tomorrow to give blood for some more tests, so I will ask them to remind me what the numbers were.

Is it worth repeating the insulin test?

Commonly HOMA-IR. Homeostatic Model Assessment of Insulin Resistance. In itself it is not a test. It’s a calculation using a formula. It uses two variables - fasting glucose and fasting insulin - to calculate a ratio of insulin resistance. The idea is to see how much insulin is being used in order to achieve the given measured glucose level. A ratio of 1.0 or below is considered normal (not much insulin required to achieve normal glucose). Above 1.0 is considered to be on the spectrum of resistance (too much insulin required to achieve normal or higher than normal glucose).

 

[DCUKMod]

@Flora123 - If you have fasted, just tell the phlebotomist/nurse you have fasted and he or she will amend the form. This usually involved her just writing on it.

 

[Member496333]

Is it worth repeating the insulin test?

Sure, if the data is available to you then it’s worth knowing. HOMA-IR would never give the same result twice, as it’s based on two constantly fluctuating variables, but a very high or very low ratio is an extremely valuable piece of data to a T2.