Thyroid Blood Tests Don’t Always Tell the Whole Story

Thyroid Blood Tests Don't Always Tell the Whole StoryIt’s a common scenario. A patient complains of fatigue, weight gain, brain fog, thinning hair, and feeling cold all the time – common symptoms of hypothyroidism, or too little thyroid hormone. But the “standard” TSH test comes back normal, and the doctor tells the patient that he or she is “fine,” with no explanation for their miserable physical symptoms.

The problem is not in the patient’s head. It’s in the TSH test.

The TSH test, thought to be the gold standard in thyroid diagnosis and treatment, often leaves a patient untreated or undertreated. TSH stands for Thyroid Stimulating Hormone, which is a hormone produced by the pituitary to tell the thyroid how much thyroid hormone to make. Typically, a high TSH indicates too little thyroid hormone in the body, while a low TSH indicates too much. The key word here is “typically.” But this isn’t always the case.

Several issues can make TSH levels decrease even while the patient is suffering from low tissue thyroid levels, and thus, is hypothyroid. Inflammation, depression, chronic illness, chronic dieting, obesity, stress, chronic fatigue syndrome, fibromyalgia, diabetes, insulin resistance, leptin resistance, and even normal aging can all cause the TSH to decrease.

The chart below shows the effect of several physical issues on thyroid hormone levels, including TSH, Free T3 (FT3), Free T4 (FT4), and Reverse T3 (RT3). As you can see, when the physical issues are absent or mild, the thyroid hormones all appear to be in the normal range. But slide the bar further to the right, at the substantial or severe level, and the hormone levels change dramatically.

At the middle of the chart, where the physical issues begin to go beyond “mild,” the TSH starts to decrease until it finally is below the normal range. This decrease in TSH would typically be interpreted as the patient having too much thyroid hormone, and the doctor would decrease any thyroid medication. But if you look at the accompanying FT4 and FT3, you’ll see these hormones also decrease. This reduction in FT4 and FT3 clearly indicates the patient is becoming hypothyroid, not hyperthyroid. FT4 could be considered the body’s “storage” thyroid hormone, as it must be converted to FT3 for the body to have energy and the metabolism to work correctly.

Reverse T3 (RT3) levels are also important to examine. Reverse T3 is a marker for reduced T4 to T3 conversion. T4 can either be converted to T3 (energy) or RT3, which is the inactive form of T3 and has antithyroid effects. If too much RT3 is made in proportion to FT3, the excess RT3 blocks the T4 from getting into the cells, effectively blocking the effect of the thyroid.

So how do you get around this issue with the TSH test in the presence of physiological stress, illness, depression or obesity, or in the elderly patient?

The best indicator of thyroid hormone levels in the cells is the FT3/RT3 ratio. In healthy individuals, the RT3 is usually below 250 pg/ml, and the Free T3/Reverse T3 ratio is greater than 1.8 (if Free T3 is in ng/dl) or 0.018 (if Free T3 is in pg/ml).

If you feel tired all the time and have the typical symptoms of hypothyroidism, and also have any of the physical issues mentioned, perhaps you should ask your doctor to look deeper into your thyroid health. All it takes is a simple blood test to measure your Free T3/Reverse T3 ratio. Getting the right tests and diagnosis could mean the difference between living a life with energy or suffering with unnecessary fatigue and other health issues.

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28 Responses to Thyroid Blood Tests Don’t Always Tell the Whole Story

  1. Dona says:

    Ok – my bloodwork is normal as stated above but I have all the symptoms, cold, chest palpitations, low temperature and live in FL and can’t find a doctor to help. Anyone know of one in the Ocala area?

  2. Joyce says:

    Have you read “Why do I STILL have thyroid symptoms? when my lab tests are normal” by Datia Kharrazian, DHSc, DC, MS. That book made the most sense to me of any I’ve read and any doctor I’ve been too. He talks about six patterns of low thyroid function — only one of which is helped by thyroid hormone. For him, it’s about the gut, the blood sugar and adrenals and the immune system. Often that’s where the thyroid problems start. Fascinating book and he has trained practitioners throughout the country in his protocols.

  3. Lorrie says:

    I had all the symptoms of low thyroid but my numbers were not showing it…fortunately, my doctor decided to treat the symptoms and not the numbers and put me on thyroid meds; it has changed my life. Not all doctors are a slave to lab tests; some actually do their homework and read the latest guidelines. He then took me off Synthroid and put me on natural thyroid because he felt it still wasn’t addressing my problems…I’ve never felt better and have lost 25 lbs.

    • Valerie Hamilton says:

      Hello Lorrie, what is natural thyroid?

      • Lisa says:

        “Natural thyroid” hormones are not made in the lab (like Synthroid), but instead come from a natural source – usually porcine (pig). Some specific brands are NatureThroid, WestThroid and Armour. These natural thyroid medications contain both T4 and T3, where a medication like Synthroid only contains T4. This is important because some patients can’t convert the T4 (storage hormone) to T3 (active, energy hormone). I’ve read that many patients feel much better when they get both T4 and T3.

    • Jacklyn says:

      Did your doctor discuss any risks of taking medicine with a normal blood test result? My doc has also put me on meds despite my blood tests but i’m nervous it may have consequences. I just started taking the medicine and am hopefully it will alleviate my symptoms but am still concerned.

      • Lisa says:

        Jacklyn, blood tests don’t always tell the whole story. My doctor also has kept me on thyroid hormones in spite of my labs. The lab numbers show that I should be hyperthyroid, but my health and symptoms are very hypothyroid. I was prepared to beg him to not reduce the meds, because I knew that I was already exhausted. I’m so thankful that he decided to look beyond the numbers. You can tell if you’re taking too much thyroid hormone because you’ll start getting symptoms of hypERthyroidism – fast pulse, anxiety, short temper, shakiness, weight loss, etc.

        • Jacklyn says:

          Thanks for the information! I was disappointed to find out that blood work has not shown any evidence of how I feel but I know when something is wrong with my body and am happy my doc has taken the time to listen to my syptoms and concerns. I already have anxiety so that is probably not a good indicator but I am paying close attention to my body for any other signs that the medicine in not needed. I’ve only been taking it for 3 days so I guess time will tell.

    • Tina Jones says:

      Any chance you live in the Chicagoland area? I’d love to know who your doctor is.

    • Angela says:

      do you happen to live in dallas fort worth?

  4. vkatseva says:

    I am so happy for you!
    I wish my doc do so for me.. Will see.

  5. WeeRainbows says:

    I live in Alberta, Canada. Our labs won’t do the Reverse T3 tests. Can you offer any other options to make the same comparissons or will the rest of the tests be enough if they will do them here?

  6. Jacklyn says:

    My blood test results also said that I have a normal thyroid range but still have all the symptoms…….fatigue, memory loss, cold hands and feet, thinning hair, and weight gain. My doctor has decided to treat my symtpoms and start me on a low dose thyroid supplement. Is this safe? Are there any consequences in doing this?

    • Cindy Watson says:

      Jacklyn, My lab tests did the same thing. They ‘appear’ normal but I have all the symptoms of hypothroidism. Will be happy when we figure this whole nightmare out. U? :)

    • Don Lee says:

      Has anyone had redness of the skin on the front of the neck over the thyroid area?

  7. Lorraine O'Connor says:

    I live in Alberta. Yes, they do the Reverse T3. Yes, you have to pay for it, but it is done.

  8. Cindy Watson says:

    Hi. I’ve been suffering with symptoms for at least 2.5 years now (I know it’s been longer than that but that is when I REALLY starting feeling like something inside me ‘broke’. My doctor just (about 2 weeks ago) put me on Nature throid but I don’t think the dosage is correct, yet. I have had the anxiety and nervous feeling way before the new medication, do any of you? Would love to talk to others about this. Most do not understand what I am talking about. Thanx!

  9. Jeny says:

    Hi Cindy,
    If you just started on the Naturethyroid 2 weeks ago, it is very likely you are not on the right dosage yet. It has to be increased incrementally and slowly. It could take a few months to get you to the correct dose. I hope your doctor will work with you based on your labs and your symptoms to get you there!

    • Cindy Watson says:

      Hi ladies,
      Well, my doctor raised my Naturethroid to 2 grains (65 mg) a day. It still is not working though. I think I feel worse than I did, I literally cannot hardly get out of bed. The tests showed that my adrenals are about ‘done’ too. Do any of you know about this? I am SO SICK of being sick and tired all the time. :( Had to share with you all; no one else really understands. Oh, and the Endo doctor that I went to about laughted me out of the office. I won’t be going back to him. I am seeing a Naturopath for what its worth. Been crying an awful lot…depression or just feeling so rotten…not sure but it is an every day occurance. Any of you going through this?

  10. Mary says:

    Cindy, Hyperthyroidism will also cause you to be really tired. It definitely will cause you to feel nervous and anxious. I would ask for a referral to an endocrinologist, if you are not already seeing one. Do your research on endos, though. All endos are not created equal, and some are much better with thyroid than others. Many endos are only “experts” with diabetes. Ask around and see if you can find someone who is a thyroid expert area in your area.
    A problem I have is that my hypothyroidism has a pituitary source and so my tsh is always very low. Doctors see that and assume I am hyperthyroid. But when it’s a pituitary source, your tsh is always low, no matter what. You would think they’d learn this stuff in medical school, but you wouldn’t believe how many times I’ve had to remind doctors of this.

    • Jay Dee says:

      Mary- How did you find out that your hypothyroidism has a pituitary source?
      I just went to the Dr. due to heart palpitations and have been referred to a cardiologist. I will follow up on that. But I think it is thyroid, and my TSH test says normal. I cannot lose weight even though I am exercising and eating right. My hands & feet are always cold. My hair is falling out. I feel unwell in hot weather. I sweat more and get out of breath faster than anyone else in my exercise group (all similar age and fitness level.) Advice?

  11. Gary Schlosser says:

    Ladies: Most of you are Ladies, it seems. But guys suffer from this problem too. The biggest problem I have is the Medical Industry. Try Kent Holtrof and the Holtrof Medical Group based in Torrance CA, (That’s LA) He has satellite clinic’s in Foster City CA (San Francisco) Phila. PA. Search the internet and I am sure you can find someone who will listen to you. I have Fibro and I’m 75. My normal Docs all know I take Holtrof’s meds and sniff “Is your doctor board certified? ” You’ve got to become more agressive about your care! It is your life not the Medical Industry. Good luck Ladies!

    • Cindy Watson says:

      I did know that men have this too but it is alot more rare; I am sorry that you are going through this too. The Endo doc that I went to also said that he didn’t know what a Naturopath was AND asked if he was board certified? How exactly do you find someone that will really listen to you and not offer you antidepressants?

  12. Cindy Watson says:

    Do any of you have hypothroidism as well as low adrenals?

  13. Erin Holley says:

    Can I go to an Urgent Care to get bloodwork done to see if my thyroid is causing all of my symptoms?

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