Hi, I'm new to this forum and just wondering if anyone has had similar experiences and may be able to offer any advice? My GP found I had blood levels consistent with hyperactive thyroid approx 2 years ago and put me on carbimazole, initially a very low dose (too low to be therapeutic from my reading) but then gradually increased the dose over the year as my levels were not improving. They also referred me to endocrinology but I waited over a year to be seen. Just before I saw the (locum) endocrinologist my levels seemed more normal so the GP added levothyroxine to try block and replace. When I saw the endocrinologist he did a physical exam and more bloods which he felt ruled out Graves disease. He suggested that it may be a lab error responsible for my results (even though my results were repeatedly in hyperthyroid range over the course of a year in my local lab) and asked me to stop taking all medication then get bloods done in 2 different labs to compare. Unfortunately he then left post and wasn't replaced and my blood results were lost to follow up by the hospital! I eventually managed to get bloods done at my GP practice 4 months ago and they were in hyperthyroid range in local lab again but in normal range in the other lab (which would fit with what the Endocrinologist thought). The GP said they had never seen this discrepancy before and couldn't explain why this happened. They asked me to get bloods rechecked in 4 months which I've just had done but unfortunately they only sent to local lab (again with results suggesting I'm hyperthyroid) and want to discuss medication again. Has anyone had a similar experience of significantly different results between labs and should I still be concerned about hyperthyroidism? I'm not on any medication just now and won't take any until they test my bloods in a different lab again as i don't want to take medicine unnecessarily! Many thanks for any advice you can offer. Ps I should probably add I've had very longstanding symptoms such as very poor sleep, heat intolerance, very frequent urination, rapid pulse/mild cardiac symptoms that I understand can be symptoms of hyperthyroidism.
Inconsistent thyroid results between labs, any ... - Thyroid UK
Inconsistent thyroid results between labs, any advice?
It would be very helpful to people if you added the actual numbers. Just saying 'in the hyper range' doesn't tell us much because we don't even know what was tested. If it was just the TSH, then the thyroid hormones should have been checked. If it was the TSH and the two thyroid hormones then antibodies should be checked. In fact, the only way to diagnose Graves' is through antibodies. Did anyone check those?
Sorry I wasn't sure what levels to post. My free T4 was consistently high at around 32, free T3 was mostly normal I think at around 6. TSH was 1.12 normal until I started on block and replace with levothyroxine when it went up to 18.2, free T4 was eventually in the normal range of 16 on 40mg of carbimazole when the levothyroxine was added by GP. When the endocrinologist tested for antibodies they just said thyroid antibodies are negative ruling out Graves. Free T4 is back up at 28 now that all medication has been stopped (according to local lab). Hope that makes sense?
It doesn't make a lot of sense, no. For one thing, we need the ranges. Results without ranges are meaningless because they vary from lab to lab.
That said, 32 is obviously high for FT4 but more in keeping with Hashi's than Graves'.
But a TSH of 1.12 is in no way hyper, so I can't understand why your GP would start you on carbi without further investigation - especially as your FT3 wasn't high.
I really think you need to find out which antibodies were tested, because they don't always test the right ones.
TPO antobodies and Tg antibodies for Hashi's
TRAB or TSI for Graves'.
I sincerely doubt you have Graves', but you could have Hashi's, so those antibodies should be tested - your GP can do that.
Also, if it were me, I would insist on a repeat test, but in a different lab - not your local one.
But, how do you feel? Do you have any symptoms at all?
My only thought would be that the 2 labs have different reference ranges causing the results to differ 🤷🏻♀️ if your having all the symptoms of an over active thyroid I would be inclined to stick with your local lab and get treated again.
I think that would have been taken into consideration. 
Thanks, I'm in the process of getting my blood done & analysed again at a different lab so will post the results from that lab as well as the results from my local lab to compare/illustrate the difference. I'll read up about hashi's too in case it could be that and check if the GP can tell which antibodies were tested for previously by the endocrinologist as they haven't said in the copy of the letter I have. All the advice is really helpful!
OK, be interesting to see the new results. If only doctors had a more logical approach to thyroid and did all the right tests without being pushed.
Hi, I have Graves, and have been on and off Carbimazole a few times over about 4 years. I generally know when I’m going overactive by my symptoms - and you have given a perfect description of what happens when my thyroid levels are too high.
I’d definitely be following up to get treatment. I never go very overactive - usually 5mg of carbimazole a day, or every other day sorts my symptoms. I feel much better when treated, sleep well, palpitations stop, pulse level drops and those trips to the toilet slow down. I’d be chasing up for treatment. Good luck hope you get sorted.
Thank you that's really helpful. What's puzzling me is the results from the other lab being normal last time they checked, even though my local lab showed elevated T4. I'm just chasing up blood results from the other lab to see what they are now but I do feel symptomatic at the moment so might need to be more guided by that! Thanks again!
I found there were several points difference between Monitor My Health and my local hospital used by my GP. The blood used was from the same draw and the ranges used were the same but my FT4 was about two points difference (I think 16 on one analysis and 18 on the other.) This difference becomes more significant when you change the results into percentages through range.
TSH was the same and there was only one FT3 result, of course.
When I queried this on this forum I think it was Helvella who explained that blood testing isn’t as reliable as we like to think it is!
Hi, so it took ages for the other Health Board lab results to come back but I finally got them. It's so strange, same thing has happened again, they are coming out normal there T4 17.3 (range 9 - 21) TSH 1.12 (0.93 - 2.29) but in my local lab T4 31.3, TSH 1.47 (I didn't get ranges for these one sorry). I'm just posting to show the level of discrepancy between labs as I find it really strange! When I saw an endocrinologist ages ago they said it could be due to ? Neutrophiles in my blood affecting interpretation at the local lab but it's quite scary to think that I could be wrongly medicated (or not) depending on which lab does the analysis! Again if anyone has a better understanding of this please let me know as I'd like to understand it better. I think as long as I'm not feeling too bad I'll just carry on without meds but if symptoms deteriorate I'll go back and get retested!
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