Thyroid UK

How to interpret and understand your blood test results

How to interpret and understand your blood test results

Your blood test results explained and lab tests reviewed

Amarillo Medical Specialists, LLP

We encourage you to read our page "How to interpret your lab tests". We have hosted this page since 1997, and it gathered more attention than we thought possible. It has been accessed over 4 million times, published in book form, is a #1 ranked site at Google, and is used as a reference on Wikipedia.

I do wish we had sites like this in the UK.

All we need now is for UK labs to provide the results together with the ranges.

6 Replies

You angel butterflylady, just had a quick look and already grasped T4 &TT4 been struggling with the reverse thing for years finally it makes sense.

I know labs ref ranges vary but it will be brilliant to have a guideline in one place with explanations.



Thank you for your kind response Woolywyn.

I am pleased you found helpful. It would appear 4.000.000. others think the same.

I appreciate and have taken to heart the comments in:

The Overview and Lab Normals

“Any unusual or abnormal results should be discussed with your physician. It is not possible to diagnose or treat any disease or problem with this blood test alone. It can, however, help you to learn more about your body and detect potential problems in early stages when treatment or changes in personal habits can be most effective.”

Once again, thank you.


i do not like the system where 'if you do not hear everything is OK'.

I have found one blood test from 2007 where T3 & T4 are at the bottom of the range. It was not mentioned and I was too ill to work it out.

More recently the kindest and caring GP overlooked raised TPO's and no mention of ridiculously high B12 although not an issue would expect over supplementation to be mentioned by GP.

Have saved Rod's site too..did not find that one either..not good at delving deep!

Someone needs to flag it for it to be discussed.

thanks jackie


I think you will find that the site below has much of the same information and covers a wider range of tests.

Look on the site and you will also see links to mobile versions - for IOS and Android.

Do this search in Google:

laboratory handbook

You will find a considerable number of lab handbooks which often contain detailed information about tests, protocols, reference ranges, etc. Sometimes the handbook is not the document you want, but it might make it easy to find the document you do actually want!



I think we must remember that for many people the picture is not black and white.

There is a vast raft of people for whom blood tests are of little or no value, so no amount of explanation of how tests should be interpreted will be of any help to them when the most important evaluation for them should be based on their symptoms. In fact I think it is counter to their diagnosis and treatment to have too rigid a system.

A large number of questions on this site come from people who are not optimally diagnosed or treated and there has to be a better way of finding ways of helping these people than relying on lab results. I think such information may be valuable to doctors, but for many patients they are a gross disservice.

Jane x


I know exactly what you mean Jane. I am concerned that both symptoms (often not mentioned to Dr as too many/not enough time/trivial)and blood results are overlooked.

2008 I asked Opthalmist would she test for Myasthenia Graves. Although I had read it does not always show up in the blood. Apparently other or better tests were being used in an Oxford Hosp. Mine was negative however my eyelids continue to close involuntarily very difficult to open if at all and general droopiness of face and all muscles floppy. A child can push me over and has done. i just learned to live with it.

This happens when stressed/after a lot (for me that is)mental physical activity.

I just found reference to people having had Graves then Hashimotos with Ophthalmoplegia (which improved with thyroxine (or treatment for HYPO).That is me to tee although the floppiness has lessened it is still happening. Cannot currently tolerate any more levothyroxine and Endo/GP make no mention of Hashimotos.

I so do not want to be put on tablets for all the multi various 'other' things.

If that makes sense?

Sorry, all a bit off topic but before I spend any money on private consultation need to compile some written info on me as I 'flop' in a consulting room..:-) I need some luck there!

I wonder was it you who mentioned. taking CoQ10. Know nothing about it but read that in above case it helps the droopy eyelids etc.,??wyn


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