Blood draw and timing

[dbrowning02]

I think I didn't have my blood drawn at the right time. Had a full panel with vitamins drawn at 8:30 (except TSH Doc left out) I take my Armour at 10:00 once a day so are my levels not going to be accurate? I had My TSH done at 11:00 held off my dosage till after but had coffee, should I scrap all and retest?

[SeasideSusie Remembering]

We should adjust timing of our meds if necessary when having a blood test. Last dose of NDT should be 8-12 hours before blood draw. So if you had your last dose of Armour at 10am the day before then you are going to have false low FT4 and FT3.

Coffee affects TSH but when taking Armour TSH is generally low so it's the FT3 result particularly that counts when on NDT.

[dbrowning02 in reply to SeasideSusie]

Thank you SeasideSusie guess I screwed that up and cost myself money. So I will have to take my meds in evening to do a blood draw in the morning, correct?

[SeasideSusie Remembering in reply to dbrowning02]

You could split your dose of Armour, take half as normal, the second half late evening/bedtime to fit in with time of test. I do this with my Levo and T3 - I normally take my T3 in one dose early morning with my Levo, so I take Levo 24 hours before the time I know I am taking test and split the T3, first dose with the Levo, second dose between 9pm and bedtime.

[dbrowning02 in reply to SeasideSusie]

got it! Thanks you again

[dbrowning02 in reply to SeasideSusie]

I was looking at test available at lab and this is what is tested with the Thyroid Panel: T3 Uptake, T4 (Thyroxine) Total, Free T4 Index (T7)

TSH.

Should my existing results for TPO, TG thyroid antibodies and CRP plus vitamins not of been affected by doing blood draw at wrong time, is that correct?

[SeasideSusie Remembering in reply to dbrowning02]

The tests needed are

TSH

Free T4

Free T3

The Total T4 test is not as useful as the Free T4 test.

The T3 uptake, from what I can gather, according to labtestsonline.org/tests/t3... is rather outdated:

This test was once used to help calculate the Free Thyroxine Index (FTI), an estimation of the free T4 concentration. It is determined from the total T4 test and some estimation of the level of thyroid hormone binding proteins. The T3 uptake test was the original test for estimating the level of binding proteins, and later versions were called T-uptake methods. These are rarely used now that there are methods available to measure free T4 and free T3 directly.

Free T3 is the most important test, it tells us how well T4 converts to T3. T3 is the active hormone that every cell in our bodies need.

Should my existing results for TPO, TG thyroid antibodies and CRP plus vitamins not of been affected by doing blood draw at wrong time, is that correct?

Antibodies fluctuate so timing is not important. CRP is an inflammation marker so not dependent on timing. Vitamins again aren't dependent on timing, we should not take them before the test on the day, we should take them afterwards but there is some advice about vitamins and testing:

* If taking iron supplements then if testing ferritin we should leave off iron supplements for a week.

* If testing serum iron we should fast for 8-12 hours.

* If taking Biotin, or a B Complex containing Biotin, we should leave this off for 7 days before any blood tests as it can give false results if biotin is used in the testing procedure (many labs use it).

* If taking B12 and we want a baseline to see how much we hold on to, we should leave B12 supplements off for 4-5 months.

[dbrowning02 in reply to SeasideSusie]

I stopped taking all vitamins a week before blood draw so those will be accurate. Thanks for taking the time to help me with this😁