Lab results confusion: Hello, I’m finding lots... - Thyroid UK

Thyroid UK

137,812 members161,641 posts

Lab results confusion

Aaaassshh profile image
14 Replies

Hello,

I’m finding lots of different ranges for all the blood tests, there is a huge variation (1000-fold differences in some cases, which makes me think they might have got the units wrong but I don’t know which are correct) for some even between different NHS trusts and I’m struggling to work out if I have an issue (even if it’s subclinical). I know my results aren’t wildly out of range, but I have multiple symptoms so I’m trying to decide whether this is worth pursuing.

If anyone could please give their opinion on my lab results based on their own experience with diagnosis and testing, that would be great. I’m particularly unsure about my anti-thyroglobulin. Or if you can point me to any decent papers/studies where I can get trustworthy ranges.

And has anyone found the conversion for the antibodies from international units into grams or moles, I can’t find the values I need to do the conversions to compare it to some of the ranges.

Thank you for any insight you can offer!

TSH - 3.55 mIU/mL

FT3 - 3.6326 pg/mL or 5.58 pmol/L

FT4 - 1.4372 ng/dL or 18.5 pmol/L

Anti-Tg - 11 IU/mL

Anti-TPO - <9 IU/mL

Written by
Aaaassshh profile image
Aaaassshh
To view profiles and participate in discussions please or .
14 Replies
Jaydee1507 profile image
Jaydee1507Administrator

Welcome to the group.

Lab ranges are specific to the lab that tested your blood. It's not possible to use a different labs ranges with your results as they are decided on tolerances within that lab alone.

Can you quote the range for your lab - in brackets after the number?

Your FT3 & FT4 look unusual with so many decimal places. Usually only 1 or 2 decimal places are quoted.

A health thyroid usually records a TSH of 2 or less, so yours at 3.55 is very slightly on the high side but likely within normal range at the moment. It might change over time but you would need to monitor that every 4-6 months.

Can't be 100% about your antibodies as no ranges quoted but they look low. Not everyone with an autoimmune thyroid condition will necessarily have positive antibodies however.

Aaaassshh profile image
Aaaassshh in reply to Jaydee1507

Thanks for the response. Those numbers have so many decimal points cause I converted them into those units as everyone uses different units so I thought it would be helpful to have both.

Yes, I guess it is assay dependent so other ranges don’t help, but I also know that the ranges used by labs are not actually that helpful as they are based on a group of “healthy” individuals which just means they hadn’t been diagnosed with anything that could influence the results at the time they were tested many years ago, so they are too broad and not necessarily reflective of healthy or optimal levels. For example they say TSH up to 4.2, but, like you say, a lot of literature is saying the cut off should be more like 2, so I don’t fully trust using their ranges. My TSH has been this high for a few years, increasing slowly over time.

The ranges were

TSH - 0.27-4.2 mU/L

FT3 - 3.1-6.8 pmol/L

FT4 - 12-22 pmol/L

TgAB - <115 IU/mL

TPOab - <34 IU/mL

Oglybogly profile image
Oglybogly in reply to Jaydee1507

How do you get the GP to test for T3 and T4? Mine always just tests for TSH.

Jaydee1507 profile image
Jaydee1507Administrator in reply to Oglybogly

There is a discrepancy beween what GP's/labs do and think we need as opposed to what we absolutely require to help us feel well. Doctors/labs believe that the TSH gives a full enough picture of how our thyroid hormone is working which patient groups know not to be the case.

Your local NHS lab likely have their own guidelines as to when they will test FT4 & FT3 such as when TSH is suppressed and FT4 is raised. These guidelines have crept in over the past years and are the reason members of this group buy private tests online.

Aaaassshh profile image
Aaaassshh in reply to Oglybogly

The GP wouldn't do it, so I had to get a private test as I didn't trust my TSH to give the full picture.

Jaydee1507 profile image
Jaydee1507Administrator

So according to this labs ranges your free results look like this.

Free T4 (fT4) 18.5 pmol/L (12 - 22) 65.0%

Free T3 (fT3) 5.58 pmol/L (3.1 - 6.8) 67.0%

Your free results arent terrible but that doesnt mean to say they are good enough for you as an individual.

Your TSH does show signs it might be struggling as it is higher than 2. Thats all we can really go on, as current UK diagnosis and treatment guidelines require a TSH above range on 2 consecutive occasions or once above 10 on the NHS to begin treatment.

Other lab ranges will be tailored to their equipment and methods which may vary.

Aaaassshh profile image
Aaaassshh in reply to Jaydee1507

Thanks for that info, I didn’t know that was the NHS policy so that’s helpful. I will try and talk to my GP, otherwise I guess I will do what I can myself to stop it getting any worse and try to feel a bit better, I’ll try and find some reputable studies on supplements and the like.

Jaydee1507 profile image
Jaydee1507Administrator in reply to Aaaassshh

I thought I posted a graph showing when TSH is highest, cant find it now. Its always best to get TSH tested at 9am and fasting. It is at its highest at that point in the day.

People with thyroid issues get low vitamin levels due to low stomach acid. Get GP to check ferritin, folate, B12 & D3, post results with ranges here. Retest thyroid at 9am fasting in 4-6 months.

TSH graph
Aaaassshh profile image
Aaaassshh in reply to Jaydee1507

Thank you. I had this 9am fasted, I tend to get all my blood tests done like that, it’s usually the best way. Thank you for the info, I’ve struggled with iron deficiency for years, finally got it sitting around 50ng/mL for a few months, still trying to get it up. I had B12, folate and vitamin D done with this test as well. My B12 and folate are alright, I’ve been supplementing for a few years as I’m on metformin which can deplete them. My vitamin D is on the low side so I’m going to increase my supplements. Thanks for all the helpful info, I will test again at the end of the year if I can afford it.

Miffie profile image
Miffie

Whilst your TSH result does look well through the range your fT4 and fT3 levels look very good to me. Antibodies don’t suggest Hashi what was your diagnosis. For me TSH has nothing to do with thyroid levels. On same ranges as yours I had TSH 3.6. fT4 13.6 and fT3 2.7! We are all different

Aaaassshh profile image
Aaaassshh in reply to Miffie

Thanks for replying. That’s helpful to know. I don’t have a diagnosis yet (and I’m not sure I ever will), it would just explain some of my symptoms so I went for a private test (the GP will only do TSH, mine has been above 2 since 2020 across 5 blood tests, and I’m taking metformin so it could really be higher than that). I hope you are getting better and finding treatment that works for you.

tattybogle profile image
tattybogle

Your results :

TSH: 3.55 mU/l (Range 0.27 - 4.2) 83.46%

FT4: 18.5 pmol/l (Range 12 - 22) 65.00%

FT3: 5.58 pmol/l (Range 3.1 - 6.8) 67.03%

Compared to these 10 healthy subjects.. your T4/ T3 are not unusual BUT the fact that your TSH is higher than about 50% of the range when paired with those T4/T3 levels IS unusual .. and this is what indicates your thyroid may be struggling to make those 'decent' levels of T4/T3.

eg Subject 8 and 9 usually have T4/T3 level like yours , but their TSH appears to be 'happy ' those levels and has not risen above about 2.5.

However you will not get any diagnosis or treatment for a thyroid problem unless your TSH continues to rise and goes over range... people with positive thyroid antibodies and symptoms of hypothyroidism may get treatment when they have 2 over range TSH results ( 3 months apart) , even if TSH still under 10, but if you continue to test negative for TPOab / TGab .. then this will mean GP's are reluctant to treat unless your TSH goes over 10

results (over 6 weeks) for 10 healthy people
tattybogle profile image
tattybogle in reply to tattybogle

useful calculator for comparing results with different lab ranges to a "% through range" so they can be compared properly thyroid.dopiaza.org/

Aaaassshh profile image
Aaaassshh in reply to tattybogle

thank you, this is really helpful!

You may also like...

Little confused by lab results

requested some tests that you all recommend, but my doc never mentions, (I’m in the US, so I’m not...

Confusing lab results

free t4 that was in the normal range, on the higher side of normal range. In addition, I have been...

Confused with lab results

I was hoping the results would have been better: Ranges are in the brackets T3: June 98...

Lab Results: Confusing

while the T4 had gone above the 75% of range, the conversion was lacking and T3 Free was less than...

Confused about lab results

weeks ago for a stomach bug. They decided to run some blood work including my tsh and T4. My tsh...