Test result ranges

[Catty2]

Hi I’m new to this forum

Can anyone tell me what the ranges are for

TSH

T4

T3

Everywhere I look they are all different

Thanks

[diogenes Remembering]

They are different because there are several instruments for testing, and their different technology results in different ranges. Also on top of that the individual lab using a particular instrument often doesn't use the manufacturers suggested range but develops their own from "healthy" patients and staff. This gives more confusion - there is a myth that the patients using a particular lab are unique in their characteristics whereas the truth is we are all the same

[shaws Administrator]

Welcome to our forum Catty2 and you haven't put any profile on your page, i.e. do you have hypothyridism, or any other problems with your thyroid gland?

If you are newly diagnosed I shall give you some hints:-

All blood tests have to be at the very earliest, fasting (you can drink water) and allow a gap of 24 hours between last dose of hormones (usually levothyroxine) and the test and take it afterwards. This helps keep the TSH at its highest as doctors are apt to adjust our dose, down, in order to keep the TSH somewhere in the range.

You take levothyroxine once daily with one full glass of water and wait an hour before eating. Usually this is a.m. but some prefer a bedtime dose - in that case you miss night dose if having a blood test next a.m. and take after test.

Always get a print-out of your results from the surgery and make sure the ranges are also stated. Labs differ in their machines and so do the ranges and it makes it easier for members to comment upon them.

GP should also test B12, Vit D, iron, ferritin and folate - all have to be optimal.

[Catty2 in reply to shaws]

Hi Shaws

I was diagnosed 20 years ago with an over active thyroid and then had a radioactive iodine tablet

So I have been on thyroxine ever since

Probably for the last 4-5 years I have not felt as well as I believe I should

I was referred to an Endo in march and he said my T3 was low and I should increased my meds from 100 to 125 and it should increase my T3 level

I felt like I was becoming overactive so I reduced my intake to 125 every other day

I then had my blood test last week and these are my before and after

T4 before 22.5 now 20.7

TSH before 1.53 now 0.07

T3 before 3.9 now 3.6

My GP ranges are

T4 9-19

TSH .35-4.94

T3 2.6-5.7

Endo ranges are

T4 11-26

TSH .35-4.50

T3 3.9-6.8

Also my Vit D is low taking 10000 for 6 weeks

As you can see both the ranges are different

I have sent my new results to my Endo ,waiting to see what he says

Any advice would be great

Sharon

[shaws Administrator in reply to Catty2]

Hopefully the new Endo will realise your T3 is on the low side and that he is capable of helping you to return to good health.

I am not medically qualified but I think you might well benefit with a T3/T4 combination and researchers have found a 1:4 or 1:3 works well for many. I do hope your Endo will prescribe the addition of T3, even on a trial basis as you have no functioning thyroid gland.

It's awful when we are told - results are good (when they mean somewhere in the range) but we feel anything but good and we need optimum of FT4 and FT3.

I have my gland and couldn't function on levo at all. When some T3 was added it was an immense difference. I now take T3 alone (self-sourcing).

[SlowDragon Administrator]

That's because nearly every lab has different ranges

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if Thyroid antibodies are raised

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw).

The aim of Levothyroxine is to increase the dose slowly in 25mcg steps upwards until TSH is under 2 (many need TSH significantly under one) and most important is that FT4 in top third of range and FT3 at least half way in range

All four vitamins need to be regularly tested and frequently need supplementing to maintain optimal levels

NHS guidelines on Levothyroxine including that most patients eventually need somewhere between 100mcg and 200mcg Levothyroxine.

nhs.uk/medicines/levothyrox...