Hi,
Please, what should be the normal ranges for the following thyroid tests:
T3
T4
FT4
TSH
Thanks
Hi,
Please, what should be the normal ranges for the following thyroid tests:
T3
T4
FT4
TSH
Thanks
This would depend on the lab and the equipment they are using. Ask whoever run the test to tell you.
There are no universal 'normal' readings for thyroid blood tests .. test ranges vary depending on the equipment used to do the test .
Different machines made by different manufacturers are calibrated differently , because the processes used to do the test are slightly different.
fT4 test ranges have a very wide variation , fT3 ranges are less varied, and TSH ranges are pretty much the same nowadays whoever makes it .
eg one manufacturer makes an fT4 test that has a (95% population reference) range of:
[7.9-14] .. another manufacturer makes an fT4 tests that has a (95% population ref) range of [12-22]
if you put the same blood sample through both tests .. you should get the same % through range , but the actual result (as a number) would be different , so you would get :
Machine A ......11 [7.8 - 14] about 50% through range
Machine B ......17 [12 - 22] also about 50% through range
Both result show the patient has an amount of fT4 that is in the middle of the levels found in 95% of the health population.
to get a '95% population range' , they test a certain amount of supposedly 'healthy' samples on the machine , they remove the highest 2.5% and the lowest 2.5% of results.. an dwhat they are left with is the 95% population range for that machine .
To interpret any thyroid blood result properly, TotalT4 / freeT4 , TotalT3 / freeT3,, you need to know the ref range used by the lab that did the test.
TSH is usually simpler.. most (UK) TSH ranges are roughly 0.4 - 4.5 ish .
( they do vary a bit , some are narrower eg [0.37 -3.6] , some are a bit wider with top end closer to 5 )
In reality is not a perfect system ... there are problems with the comparability between some tests :
healthunlocked.com/thyroidu.... freet4-testing-difference-in-reference-ranges-reading-matter-for-a-rainy-day-.
There are also significant issue's with the use of the word 'normal' :
helvella.blogspot.com/p/the... The normal range: it is not normal and it is not a range.