Better method for assessing TSH normal ranges

We've just got a paper accepted in Nuklearmedizin which describes a better way of determining TSH reference ranges. What it does is minimise the uncertainties at each end of the range for assessing cutoff points. This may be technical for Healthunlocked, but it does at least challenge conventional ways of deriving ranges and for this forum, the range seems to be around 0.5-3.5. You could use this to challenge higher ranges and diagnosis from them.

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19 Replies

  • Thanks diogenes. I look forward to its publication.

    My first TSH test was about 2. It gradually rose to top of local range (tiniest bit over 5.0) and at that point the continual rise convinced my GP. However, with hindsight, I think I was hypo at 2, and most definitely so at 3.5. Last tests have been around 1.6 and I feel OK there. So a move towards 0.5-3.5 seems a definite step in the right direction.

  • That's very good news, just to highlight the coming New Year.

    Do you think the BTA would take notice of this and change their stance, i.e. still saying that a patient reach 10 before medicating.

  • Diogenes, is this the correct link to the journal? PR

  • That's correct, but I'll put the article into HU if its wanted, maybe through Louise Warvill when it is in publication.

  • Diogenes, that would be appreciated since it will be behind a pay wall and I bet I'm not the only one that would like to read it. PR

  • Diogenes, I'll look forward to reading it too and if I don't understand it maybe you'll do an idiot's guide for me :)

  • TSH testing is useless when taking ANY form of thyroxine!!

  • I'm afraid I disagree. A primary use for TSH in treatment is to check whether patients are taking the hormone supplement or not. A surprisingly large proportion of patients forget to take their dose for a while, then remember that they have a doctor's appointment in the morning,, and hastily take their dose hoping that they'll appear normal on presentation. They don't; they will have the classic sign of a noncomplier - high TSH, normal FT4.

  • 7You can disagree all you want but I will stick with the fact that its true.

  • Hmm. It's so common to blame the patient. My TSH has risen every year on meds even though I take them consistently (however it's still low, as I'm pretty sure I don't have primary hypo). I have low normal T3 and T4.

    I used to get the same spiel when I was breathless and it was assumed I wasn't taking my asthma meds - it was actually rock bottom B12.

    How could you possibly forget to take your levo when not taking it makes you so ill? And you wouldn't take it anyway before an appt in case a blood test was involved.

  • I agree that blaming the patient is all too common. It is, of course, one thing to notice blood results that could be indicative of failing to take a medicine, and quite another to take a fragment of evidence and assume that is the only possible explanation. Even if it were the only explanation, it is important to understand why someone would do so and seek to help them. Not treat them like naughty schoolchildren. Standing on the naughty step does not help thyroid hormone levels.

    We have had a surprising (to me) number of people post here that they have forgotten to take their levothyroxine. Sometimes for days, sometimes for weeks or months. Some years ago I knew someone who would take/not take their levothyroxine for moths at a time. She said that she really didn't notice much difference. I suspect low but continuing thyroid function and an insufficient dose (or need for liothyronine). She was never right.

    Not everyone is aware of that they should not be taking levothyroxine before a blood draw. (Quite a lot of medics deny it has any impact.) So that also rings true.

    I guess that anyone who has been reading here for a while would be far less likely to do either of these. But there are a lot of people who do not come onto any internet site for thyroid.


  • There are also medics that tell you to take it before a test.

  • Glynisrose, it's not useless for those of us who need their TSH suppressed to prevent cancer recurrence or those whose TSH needs to be suppressed to prevent TED worsening.

  • Sorry: a surprising number of people do, and are caught by the false TSH/FT4 combination.

  • Then that is probably the fault of the doctor who hasn't bothered to explain the nature of the illness to the patient. If people don't understand the importance of taking their tablet, it's not surprising if they 'forget' to take it. After all, they always explain about the importance of taking your antibiotic up to the last dose, so why not tell people the importance of taking your levo (or whatever)?

    There are far too many doctors that just say take this pill every day and you'll be fine (and too many that say if you are taking it, there's nothing wrong with you!) without giving any information - we see these poor patients on here all the time, asking what the hell is going on. Can doctors not be bothered? Or are they just too ignorant?

    It's time they were called to account instead of blaming their patients - which they're far too quick to do, anyway, because it makes life easier for them. And it's certainly time to drop the TSH test given how dangerous it is to dose by, given how badly it messes up people's metabolism (not to mention their lives!).

    As much as I appreciate your efforts to improve our lives, dear Diogenes, I still believe the time has come to find a better way to diagnose and treat thyroid disease rather than using a pituitary hormone that rarely correctly reflects thyroid status or the way people feel.

    Hugs, Grey

  • All the available tests (TSH, FT4,FT3) have their strengths and weaknesses in different areas of thyroid function testing. They have to be applied and most importantly properly interpreted in the right and appropriate conditions. No regime should be based on one of these tests alone, whatever it is. TSH is inappropriate and suboptimal for monitoring therapy, whereas FT3 will be better. FT4 is only moderately useful to check dosage. But TSH and FT4 are useful for screening apparently normal people. FT3 is no good with accompanying non thyroidal illness. Horses for courses! I aim for the return of the kind of testing regime that was for a short time in practice before TSH-only diagnosis took over to the detriment of many who visit this forum (and others). But do accept that patients as a group are not angels and some can be deaf to what the doctor advises.

  • IF the doctor advises. I, for one, was given no information after diagnosis, I had to find out for myself what it was all about. The endo was dismissive of questions, and when I felt worse taking levo than I did without it, she just told me it was because I had a negative attitude! With doctors like that, who needs... the TSH test!

    Yes, good for screening, but lowering the top level is not going to make it any better for dosing by.

    There are very few angels on this earth, be they patients or doctors, but developing a test to catch patients out when it's not even fool-proof, just seems to me like a waste or resources.

    Hugs, A Patient

  • The paper has hit PubMed:

    Nuklearmedizin. 2015 Jan 8;54(1). [Epub ahead of print]

    Reference range for thyrotropin. Post hoc assessment.

    Larisch R1, Giacobino A, Eckl W, Wahl H, Midgley JE, Hoermann R.

    Author information

    1Prof. Dr. Rolf Larisch, Department of Nuclear Medicine, Klinikum Luedenscheid, Paulmannshoeher Str 14, 58515 Luedenscheid, Germany, E-mail:


    Setting the reference range for thyrotropin (TSH) remains a matter of ongoing controversy.

    Patients, methods: We used an indirect method to determine the TSH reference range post hoc in a large sample. A total of 399 well characterised subjects showing no evidence of thyroid dysfunction were selected for definition of the TSH reference limits according to the method of Katayev et al.. To this end, the cumulative frequency was plotted against the individual logarithmic TSH values. Reference limits were calculated by extrapolating the middle linear part of the regression line to obtain the cut-offs for the 95% confidence interval. We also examined biological variation in a sample of 65 subjects with repeat measurements to establish reference change values (RCVs).

    Results: Based on these, the reference interval obtained by the novel technique was in close agreement with the conventionally established limits, but differed significantly from earlier recommendations.

    Discussion: Following unverified recommendations could result in a portion of patients with subclinical thyroid dysfunctions being missed, an important consideration in a setting with a high prevalence of thyroid autonomy.

    Conclusion: Indirect post hoc verification of reference intervals from a large retrospective sample is a modern approach that gives plausible results. The method seems particularly useful to assess the adequacy and performance of reference limits reported or established by others in a particular setting. The present data should encourage re-evaluation of reference systems on a broader scale.


    TSH; reference range; thyroid hormones




  • I myself cannot get the article without paying, but one of the coauthors will transmit it so that it can be posted on HUK through an attachment. I'll append an explanation of the approach as well when the paper is available to me.

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