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Mary Shomon

Why Dr. Richard Shames Prefers Capillary Fingerprick / Blood Spot Tests for Thyroid Testing and Evaluation

By April 16, 2009

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I frequently feature information from Dr. Richard Shames, co-author with his wife Karilee Shames, RN, PhD, of several popular books on thyroid disease, and a Harvard and University of Pennsylvania educated doctor who has worked with thyroid patients for several decades. Recently, Dr. Shames told me that he is increasingly relying on specialized capillary fingerprick/blood spot testing for thyroid levels, rather than the traditional thyroid blood tests and analysis done by most laboratories. This Q & A looks at Dr. Shames' opinions about this form of testing.

Mary Shomon: Why are you increasingly preferring blood spot testing for thyroid tests, rather than standard blood lab tests?

Richard Shames, MD: What I am telling both patients and colleagues is that the reason is simple. While regular testing does a fine job for a great many people, for others (especially the more difficult-to-diagnose cases), these are new and better tests -- which in many cases are even available without a doctor's order -- that evaluate these hormone systems more effectively and more completely in my opinion.

After doing thyroid testing by regular venous blood draw for these last 25 years of hormone practice, I have come to see the superiority of a new technology that appeared in the prior decade. Osteopaths, Nutritionists, Chiropractors, and Naturopathic Doctors were using the new technology and advised us during some of our hormone seminars to give it a try. What I found, as a medical doctor, was that the blood spot testing from capillary fingerprick gave more definitive results for my most difficult thyroid cases.

For example, when a patient who had regular blood lab tests was still uncomfortable despite normal results, I would do the blood spot finger prick analysis. (I use the tests from ZRT Laboratory.) This new testing sometimes showed that this supposedly "normal" patient was actually too high or too low in thyroid hormone. When I followed the direction suggested by the new tests in terms of making a change in prescription, the patient frequently finally started to feel better.

Also, when I had a patient who had previously seen many other doctors, including endocrinologists, and had been repeatedly told that they didn't have a thyroid problem because their blood tests were normal, I gave these folks the new testing of finger prick bloodspot analysis. Often I saw thyroid antibodies where there had been none previously, or I saw abnormal TSH values on the new testing that regular blood tests had shown as normal -- even using the new range of normal.

This new testing seemed to be so much more helpful to my more difficult patients that I started using these tests for most of my patients, to good advantage. I wanted to understand why this test was superior.

Mary Shomon: Why do you think that you're seeing what you consider to be more accurate results with this new testing, versus traditional tests?

Richard Shames, MD:I spoke with Dr. David Zava, the founder of ZRT Labs, who explained that capillary blood is a more accurate place to measure true levels of available thyroid hormone. Not only is the home-based finger stick test less invasive, less costly, and less of a hassle than having to go to a draw station, but also it has the potential of being more accurate because of where the blood is drawn from.

Moreover, there is an added benefit of taking a few drops of blood and having it dry in seconds on a piece of specially treated filter paper that is then analyzed by very sensitive modern equipment (chemiluminescense method). The dried sample is much more stable than thyroid hormones in a liquid form (a tube of blood serum) as is done in regular labs. This is especially true of the fragile pituitary hormone TSH, considered the gold standard for thyroid evaluation. The molecules of these hormones will degrade more rapidly in a liquid form than in a solid dried state.

People should know that the blood that is drawn in the morning at almost every lab in the US is not run through the machinery for analysis until that evening. During that time, your hormones - especially the important TSH - may end up showing lower on your test result than is accurate for you.

There is the important concern about TSH values: it is not a regular hormone, it is a pituitary hormone that according to the best standards should be refrigerated properly once drawn. Most big labs have satellite centers (draw stations) that courier the blood samples to them. Are these kept at exact proper temperature? Hardly ever. TSH serum is rarely refrigerated.

What this means is that you could be low thyroid with abnormally high TSH but by the end of a long day in a test tube, your levels of TSH that are able to be measured will now be in the normal range. If that's not bad enough, here's something even worse: if you are getting inadequate levels of medicine once you're taking thyroid pills, this inaccuracy could convince your doctor that you are on enough or even too much medicine, and he will likely lower your dose even though you're struggling at the present dose.

* * *

If you are interested in specialized capillary fingerprick/blood spot testing for thyroid levels, there are two ways you can obtain this sort of testing. First, your practitioner can order these new tests for you, in addition to or instead of the traditional tests, via ZRT Laboratories. These new tests are also available without prescription to health consumers, via home test kits. If you want to self-order, you can order directly from ZRT, or save money by getting a free membership in an independent patient consumer advocacy group, such as Canary Club, where you can benefit from the group's volume test discount. More information about ZRT and the Canary Club is available in my article on self-testing for thyroid and hormones.

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Photo: Richard Shames, MD

April 17, 2009 at 4:36 am
(1) Nikki Prohaska says:

I am familiar with ZRT labs doing blood spot testing. My question is do they preform the Free T3 and Free T4 along with the TSH as a blood spot test? Can a thyroid patient order specific thyroid testing like FT3/FT4 – TPOab or Tgab tests from ZRT?

April 17, 2009 at 8:59 am
(2) Jim Pascale says:

I have to ask – does the doctor have nay financial ties to this lab?

April 17, 2009 at 9:39 am
(3) Mary says:

No, Dr. Shames does not have a financial interest in this lab.

April 17, 2009 at 10:37 am
(4) Dana Thompson says:

I had used a home test kit a few years ago (although NOT from ZRT) when I had no access to normal testing (no insurance, no doctor). I had been out of thyroid meds for about 6 months & had decided that if the home test kit showed high TSH I would find a doctor that would accept a new patient with no insurance& pay out-of-pocket. The test kit showed me to be low-normal (.0something). A week later my new endo tested me – my TSH was actually 126. I would advise to be very cautious when using any home testing.

April 17, 2009 at 11:04 am
(5) Jim says:

Thank you Mary. I do appreciate your reply. I felt compelled to ask since so many doctors today hide their financial interests, to the detriment of thier patients. Kudos to Dr. Shames. I am quite interested in a home test for my thyroid condition.
Jim Pascale

April 17, 2009 at 5:11 pm
(6) Vince says:

Will have to ask if this test is available in Australia.

April 17, 2009 at 7:31 pm
(7) Bev says:

Interesting article. I would love to get this blood test myself but I live in New York State the only state that does not allow patients to order their own blood tests.

Peace, Love and Harmony,

April 17, 2009 at 7:52 pm
(8) Mary says:

Does this test work also on pets. My dog has been diagnosed with hypothyroid and he is on his second type of meds at .8mg. I feel he is not really doing so well even though his tests showed T-4 at 3.3. He is restless, pants alot and seems to run a low grade fever alot and generally not his normal self.

April 17, 2009 at 7:54 pm
(9) PattiC says:

Very interesting interview. I wonder if serum for cholesterol and tsh is refrigerated? I just got my ZRT blood spot result for Vitamin D (25OHD) a few minutes ago. I joined GrassrootsHealth a few weeks ago. http://www.ordervitamindtest.org I joined for 1 year twice a year testing. It’s $40 each time now. My D was 93 ng/mL, :-)

April 17, 2009 at 8:40 pm
(10) V. Pinker says:

I was going to join the “Canary Club”, but after reading their “TERMS AND CONDITIONS”, it upset me that they expect one to read all those books including any future ones or info. Some of us don’t the have time to just sit down and read book after book, and many times it takes FOREVER just to get to the part in the book you’re interested in. I don’t have the patience to sit down with books. They’re too long and drawn out.

April 18, 2009 at 5:49 am
(11) amani bengawi says:

It’s fantastic to have a home bazed thyroid test , because in my country the classic test is very expensive and it is carried in selected laboratories only. We hope such technique find its way to Sudan.

April 18, 2009 at 6:22 pm
(12) Darrin says:

I am a board certified antiaging physician and preventive medicine specialist with 30 years experience, specializing in thyroid treatment.

Serum isn’t the ideal reservoir to conduct thyroid testing, nor is saliva or urine. The truth is we can’t sample cellular thyroid receptor binding occupancy which is the only thing that would be nice to measure. So any test mentioned is at best, mediocre and a transient marker. Capillary blood has always been more unreliable than venous sticks – noone would question that. So whether it is more stable on a card than in a spun sample is irrelevant because the initial sample isn’t valid! It doesn’t matter how good the analysis is when the test is bad from the start.

In the end, name a specialist worth his/her salt that treats thyroid based on any number.
Isn’t that the point? This doctor is arguing a case that is mute, and demonstrates to me that he knows nothing about thyroid managment, nor does ZRT who clearly is working on profiteering rather than preventive health enhancement.

Don’t be so quick to jump on this kind of testing gimmickry, it isn’t the next step to where we all want to go.

April 19, 2009 at 12:52 pm
(13) UK Thyroid Patient says:

It is a blood test! What about the symptoms?
What is the patients temperature and pulse? etc etc.

If you crash your car/Auto after it is serviced, and the oil analysis states the car is road worthy. What can you do? Despite the fact that it was issuing clouds of smoke from the exhaust etc,.

To use the Amercian vernacular, ‘lets get real here’.

April 19, 2009 at 1:41 pm
(14) Karilee Shames says:

To Dr. Darren, wow, we’re not sure what country you’re reporting from? When you say name a specialist who treats according to just the numbers, we can name hundreds, possibly thousands if we had the time… ask any thyroid patient. We are working to empower people who are being given terrible treatment by your colleagues. Our strongest recommendations, as evidenced in our books, is to take the questionnaires and consider a sample of thyroid medicine if you have a strong family history, signs and symptoms, or associated conditions. You need a wake up call from the thousands of people who do read this website and have not been able to get the help they need from specialists! Need to get real and understand that your profession is failing these patients, before you can help them better. Best wishes

April 19, 2009 at 1:44 pm
(15) Karilee Shames says:

To V.Pinker – sorry if the terms of the Canary Club offended you, but you must realize that for you to feel better you will need to learn much more about your condition. Many people do not enjoy reading, we understand that, but you need to know more about your condition before going to speak to your doctors and asking for specific help; you need to know the “Why” – that’s what makes this approach different from most regular docs, who pat you on the head and tell you not to worry, just to listen to them. If reading isn’t your thing, we hope you can find other ways to learn more. Blessings

April 19, 2009 at 1:46 pm
(16) Karilee Shames says:

To the person asking about whether Dr. Shames has any financial reward from this lab, absolutely not! That is illegal. He does however believe strongly in the evaluations they provide. Best wishes

April 19, 2009 at 4:44 pm
(17) Kathy says:

I’m open to the finger prick test, especially since my TSH fluctuates from test to test, which is frustrating. I am careful how I take my Synthroid, which is a picky drug, as you can’t eat walnuts, calcium, iron, soy products, etc. As instructed, I have always taken it on an empty stomach. In the past 6 years since my thyroidectomy, I have yet to remain on one single dose of synthroid for a sensible period of time. Maybe the finger prick test would help.

April 20, 2009 at 5:53 pm
(18) Think about this ... says:

Sorry Mary, this sounds like pure pasture-patties.

I see a huge wall of bull being shilled by the ‘Doctor’…

Big fancy sounding word –
“chemiluminescense” – ooooh

“The dried sample is much more stable”

Nope. What next, live blood analyis??

“Osteopaths, Nutritionists, Chiropractors, and Naturopathic Doctors were using the new technology and advised us during some of our hormone seminars to give it a try.”

What about legitimate MDs – especially endocrinologists – saying about this method?

“People should know that the blood that is drawn in the morning at almost every lab in the US is not run through the machinery for analysis until that evening.”

Because obtaining a sample under way-less-than-ideal conditions, then mailed off through the postal system is so much better?

“The molecules of these hormones will degrade more rapidly in a liquid form than in a solid dried state.”

Again, days in the postal system is sooo much better??

“There is the important concern about TSH values: it is not a regular hormone, it is a pituitary hormone that according to the best standards should be refrigerated properly once drawn. Most big labs have satellite centers (draw stations) that courier the blood samples to them. Are these kept at exact proper temperature? Hardly ever. TSH serum is rarely refrigerated.”

‘Cause the post office always treats lab samples idealy??

Please supply actual information about this modality, not this infomercial flogging.

Give me a break. Snake-oil anyone??

April 21, 2009 at 10:07 pm
(19) DANA says:

HELP!!!! I am so desperate for answers I don’t know where to turn. I had my thyroid ablate in March of 2008, have been on a roller coaster ride since then. On top of that have been raising a baby by myself, which has been the most difficult task I have ever done. Anyway, My TSH is 26.54 and I feel better than I have at any other level, WHY is this, no one can answer this not even my doctors. I am still extremely exhausted but not so hyper and crazy. I need help if anyone can give me any direction, I would appreciate it. Thank you!!

April 22, 2009 at 9:50 pm
(20) Kathryn says:

Dana, I was in the same boat as you. I had a partial thyroidectomy in Aug 75 and my second child in June 76. My husband left me in Dec. 75. It is a very difficult situation. For about two years after my surgery, I lost weight, felt great, and had enormous amounts of energy (despite all the personal turmoil. Then, I slowed down, started gaining weight, and despite repeated blood test over the next 25 years, was told my thyroid was “normal.” When asked if the levels were fine, why did I still feel the way I did, one doctor responded, “Well, it has to be something else.” Moral to this long story…things do get better. If necessary, try to find a doctor that will treat the way you feel, not on the basis of test results…and if you get a response like I did…..run, run, run. I know you are going through a really difficult time, so hopefully I can keep in touch. I am a good listener. Hang in there!!!

April 27, 2009 at 12:56 am
(21) Karen Stone says:

Regarding your question about thyroid tests for pets: You need to go back to your vet, get another blood sample drawn on your dog, and have your vet send the sample to Antech Labs down in Calif. (your vet knows about this lab and how to do this). There is a vet. specialist there named Dr. Jean Dodds who has made a career out of studying the canine thyroid. I had it done for my dog, she halved the amount of medication that my regular vet had prescribed, and my dog was perkier, happier, and seemed more her normal self. It can be hard to regulate thyroid medication in animals because they can’t tell us how they feel and sometimes we aren’t aware of the extent of their problems or discomfort until they become extreme. (By the way, I am a licensed veterinary technician….)
Good Luck!

January 11, 2010 at 11:15 pm
(22) Jean says:

the blood spot test is great, I was on HRT and was pretty sure sometime wasn’t right the regular blood draw didn’t show any problem but when my hair started to fall out I was freaked out and insisted on some answers my doctor had me do a blood spot and that was shocking I was 5 times higher estrogen than I should of been. Problem fixed at last,,,,

March 11, 2013 at 11:21 pm
(23) kathy says:

I had blood tests done and the results were 3.87 reference 0.4-4.50 mIU/L
what does this mean. my dr. would not tell me

August 15, 2013 at 2:09 pm
(24) trev says:

Your TSH is below the upper limit. This may mean you are becoming hypothyroid, but not necessarily so.
It could also take you a long time to arrive at the upper limit.
Yout Doc is wary about discussing it probably because treatment is life long and not easy to get right. You could well feel worse on treatment for a while, too.
If your symptoms are continuing -you will have to push for a further test. Anything above 3 could be of interest- but not everyone will have problems they can identify with at this level -as we’re all different.
Don’t worry overmuch about all this- and try to get regular exercise in fresh air and keep to a good diet in the meantime.

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