Tsh ranges

[Rush2112]

Hi

Cane anyone tell me why people keep asking to post ranges next to blood results I understand areas can differ but surely

Unless you are boarder line then it shouldn't matter

Perhaps it means something different than I thought

[shaws Administrator]

You would think, reasonably, that once we have the blood test results that should be sufficient but due to labs having different ranges throughout the country. It is important that these are given as well so that members are more fully informed and can answer better. That's why it's always better to get copies for your own records and then you know what the labs use, unless of course another lab is used. It could mean the difference between being too low or too high.

[Clutter]

Rush2112, how can you tell whether one is borderline without the range? The ranges vary considerably across the UK and the world. Someone could say they have a FT3 of 2. In some ranges this would be dreadfully low and below range but in others it will be top of the range.

[Rush2112 in reply to Clutter]

So does that mean it depends we're you live in the country to whether you are treated for thyroid problems

[Clutter in reply to Rush2112]

Rush, no it depends where you are in your area's lab ref range and how clued up your GP or endo is. If you are borderline with positive autoimmune thyroid antibodies some doctors will take the view that thyroxine treatment will delay progression of the disease and inevitable destruction of the thyroid resulting in overt hypothyroidism. Others will treat when TSH is above range but some will not treat until a patient is overtly hypothyroid ie TSH >10.

Lab ref ranges are based on mean average results of population samples in the lab's area. Unfortunately people with subclinical hypothyroidism (TSH <10 with in range FT4 and FT3) haven't always been screened out.

thyroiduk.org.uk/tuk/about_...

[Hidden]

This kind of answers my query elsewhere about a postcode lottery, but why isn't there a national range? Is it to do with different testing methods in the various labs, and if you took your results to another area with different ranges would they want to retest using their lab ranges.

[helvella Administrator]

The labs around not only the UK but the world use different technologies. They also use different units.

Theoretically, if you have, say, a TSH test done at many laboratories the results should be similar - in that if you are right at the bottom of the range, that would be the case at every lab even if the number that is the bottom of the range varies. (Similarly for top of range and mid-range - for easy examples.)

When a lab changes their process, quite likely to an improved technique, they will usually change their reference ranges. And, if your number was top of range before the change, then the next day with the new range, it should also be top of range. (Sometimes ranges change when improvements are made to the discrimination of tests. E.g. when they added the removal of TSH antibodies to TSH testing techniques, TSH ranges fell because test results were no longer being artificially inflated by the antibodies.)

That is, you could have a TSH test one day and get a result of 0.5, and have it repeated the next day getting 0.3. But you might not have changed at all - if the lab has changed their technique and range at that time. So looking at a graph of your results would show a step - but one that is lab-based not patient-based.

Where different units are used, the reference range can help to avoid falling into traps of misinterpretation. The ranges below are possible ranges for Free T4 - in the USA they use ng/dL, in the UK we use pmol/L.

Normal adult 0.7 to 1.4 ng/dL or 9 to 18 pmol/L

If someone quotes a value of, for example, 5 - does that mean they are very hyperthyroid (USA) or very hypothyroid (UK)? We get quite a number of people posting their results from labs in many countries.

We quite often see people posting T3 results (not as often as we'd like, but that is another story). All too often they don't clarify whether, or maybe don't even know, if it is a Total or Free test. These are possible UK ranges for the two tests:

Total triiodothyronine 0.9 to 2.5 nmol/L

Free triiodothyronine 3.1 to 7.7 pmol/L

So if you have a T3 test and get the result 3.0 - is that a high Total T3 or a low Free T3? Numerically you have no idea. The units help as one unit is a thousand times larger than the other but the actual range does help to back that up as well (i.e. that it is not a simple typo). And both ranges vary enough to be important cross the various UK labs. (USA units are again different to those in the UK and can cause havoc with T3 test interpretation if we do not take the right ranges into account.)

Rod

[immuneaction]

their is not a national range as the top of the range for TSH can not be established.

the normal range is 0.1-1.5 in a healthy female and 1.8 in a male. so as it go`s up and down a lot it is not the best test their is, also it is a pituitary test, which could take years for the TSH to raise up. the best test is the T3 and TPOab which has to be over

o.6 to be positive for hashimoto`s disease, but doctors don`t understand this and don`t treat until it is in the 100`s. the T 3 should be at the top of the range and the T4

just below this in the top third of range. the reference interval`s are like a ruler if

you are a size 5 shoe and your friend is a size 7 you are bother normal but if that is the

case why are doctors saying we are normal when out TSH is still in the range , i was in the range and very hypo, so what does that tell you. something is not adding up.

so why don`t they treat us and our symptoms , duh. WHY ARE WE WAITING UNTIL

OUR GLANDS ARE DEAD.