Do you always fast before your blood tests?

[tastyfood]

I test regularly for things like prolactin, TSH, total cholesterol, and other important tests. I typically test early in the morning, fasting, for consistency.

I am starting to think if I should at least once test in a non fasting state. Being fasted is the most stressful time of the day, and I want to check what effect my normal routine (having a good breakfast) has on the tests.

For example, my ACTH is always high, above range at times, and testing in a fasted state could be contributing to that.

Any experiences to share?

Thank you!

 

[Nokoni]

I test regularly for things like prolactin, TSH, total cholesterol, and other important tests. I typically test early in the morning, fasting, for consistency.

I am starting to think if I should at least once test in a non fasting state. Being fasted is the most stressful time of the day, and I want to check what effect my normal routine (having a good breakfast) has on the tests.

For example, my ACTH is always high, above range at times, and testing in a fasted state could be contributing to that.

Any experiences to share?

Thank you!

I don't have an answer but I think it's an excellent question, so have a bump. I think the fasted state may be needed for testing related to glucose control, but if you're less concerned about that it would seem to make sense to eat normally. And for me the fasted state is radically abnormal.

 

[loess]

I test regularly for things like prolactin, TSH, total cholesterol, and other important tests.

Just curious, what all tests do you consider as important to do regularly?

 

[InChristAlone]

Postprandial of about 3-4 hours gives a better picture of how food is interacting in your body.

 

[Sefton10]

I think the key is whichever time you choose testing at the same time each time so you’re comparing apples to apples.

 

[tastyfood]

I think the key is whichever time you choose testing at the same time each time so you’re comparing apples to apples.

Yeah. This is one of the arguments in favor of doing the next test fasted again.

 

[tastyfood]

Just curious, what all tests do you consider as important to do regularly?

Similar to what you hear from Peat or Roddy: Total cholesterol, TSH, prolactin, PTH, total testosterone in my case.

 

[tastyfood]

I don't have an answer but I think it's an excellent question, so have a bump. I think the fasted state may be needed for testing related to glucose control, but if you're less concerned about that it would seem to make sense to eat normally. And for me the fasted state is radically abnormal.

I don't care about fasting glucose, and from what I'm seeing, all the other tests that I do don't require fasting.

It bothers me to do tests fasting and then get high results for things like ACTH. I wonder what a difference a light breakfast will make to the ACTH results, for example.

 

[Nokoni]

high results for things like ACTH

Exactly. You don't know if it's because you have a problem, or because you're just hungry.

 

[tastyfood]

Exactly. You don't know if it's because you have a problem, or because you're just hungry.

Using the ACTH example again, the test isn't listed as requiring fasting. It is only required to do it between 7am to 10am.

Even some of the test where fasting is recommended, there is a lot of controversy. For cholesterol, food is said not to alter the results. Perhaps triglycerides could go up momentarily but that's it.

 

[jdr75bulldog]

I test regularly for things like prolactin, TSH, total cholesterol, and other important tests. I typically test early in the morning, fasting, for consistency.

I am starting to think if I should at least once test in a non fasting state. Being fasted is the most stressful time of the day, and I want to check what effect my normal routine (having a good breakfast) has on the tests.

For example, my ACTH is always high, above range at times, and testing in a fasted state could be contributing to that.

Any experiences to share?

Thank you!

Not sure but I think Dave Feldman recommends mid-morning blood testing. He talked about it regarding triglycerides on preparing for your best blood test. Triglycerides are naturally higher first thing in the morning and after two hours they come down significantly.

 

[tastyfood]

Not sure but I think Dave Feldman recommends mid-morning blood testing. He talked about it regarding triglycerides on preparing for your best blood test. Triglycerides are naturally higher first thing in the morning and after two hours they come down significantly.

For prolactin, a urologist vehemently recommended I don't test before noon. Your point about trigs is good.

I did my tests in a non-fasted state this time, and it might have made things more confusing.

From a study:

"...and sharp peaks have been observed following food ingestion".

I did my test at 8am, about 40 min after having a light breakfast and taking thyroid. Digestion can be somewhat stressful, so it's possible that actually contributed to elevated results. I put my body through a stressful experience (7 to 8 tubes of blood extracted from me), while I was still digesting food.

 

[jdr75bulldog]

I generally only fast when they are checking lipids like triglycerides and cholesterol.