Guest guest Posted June 14, 2007 Report Share Posted June 14, 2007 > > I would like to understand the relationship between free and total T3 > and T4. What is the ideal relationship and what does it mean when > the ratio is not ideal? > > -- > DA: Your question can best be handled elsewhere on the web.... as a long-suffering hypothyroid person, I found a wealth of info on the about.com site - put " thyroid " in the site's search engine and you'll get a section overseen by Shomon {?,think that's right] She has tons of info, and also how to read your test results. Good luck! DA Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2007 Report Share Posted June 14, 2007 > > I would like to understand the relationship between free and total T3 > and T4. What is the ideal relationship and what does it mean when > the ratio is not ideal? > > -- > DA: Your question can best be handled elsewhere on the web.... as a long-suffering hypothyroid person, I found a wealth of info on the about.com site - put " thyroid " in the site's search engine and you'll get a section overseen by Shomon {?,think that's right] She has tons of info, and also how to read your test results. Good luck! DA Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2007 Report Share Posted June 14, 2007 > > I would like to understand the relationship between free and total T3 > and T4. What is the ideal relationship and what does it mean when > the ratio is not ideal? > > -- > DA: Your question can best be handled elsewhere on the web.... as a long-suffering hypothyroid person, I found a wealth of info on the about.com site - put " thyroid " in the site's search engine and you'll get a section overseen by Shomon {?,think that's right] She has tons of info, and also how to read your test results. Good luck! DA Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2007 Report Share Posted June 14, 2007 > > > > I would like to understand the relationship between free and total T3 > > and T4. What is the ideal relationship and what does it mean when > > the ratio is not ideal? > > > > -- > > > > DA: Your question can best be handled elsewhere on the web.... > as a long-suffering hypothyroid person, I found a wealth of info on the > about.com site - put " thyroid " in the site's search engine and you'll > get a section overseen by Shomon {?,think that's right] > She has tons of info, and also how to read your test results. Good luck! > DA I searched and searched. Could not find anything. I have tried looking at the about.com website. It is so busy and cluttered, I literally can't take in any information from it. It's like beating my head against a wall. Horrible design, IMHO. -- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2007 Report Share Posted June 14, 2007 > > > > I would like to understand the relationship between free and total T3 > > and T4. What is the ideal relationship and what does it mean when > > the ratio is not ideal? > > > > -- > > > > DA: Your question can best be handled elsewhere on the web.... > as a long-suffering hypothyroid person, I found a wealth of info on the > about.com site - put " thyroid " in the site's search engine and you'll > get a section overseen by Shomon {?,think that's right] > She has tons of info, and also how to read your test results. Good luck! > DA I searched and searched. Could not find anything. I have tried looking at the about.com website. It is so busy and cluttered, I literally can't take in any information from it. It's like beating my head against a wall. Horrible design, IMHO. -- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 14, 2007 Report Share Posted June 14, 2007 > > > > I would like to understand the relationship between free and total T3 > > and T4. What is the ideal relationship and what does it mean when > > the ratio is not ideal? > > > > -- > > > > DA: Your question can best be handled elsewhere on the web.... > as a long-suffering hypothyroid person, I found a wealth of info on the > about.com site - put " thyroid " in the site's search engine and you'll > get a section overseen by Shomon {?,think that's right] > She has tons of info, and also how to read your test results. Good luck! > DA I searched and searched. Could not find anything. I have tried looking at the about.com website. It is so busy and cluttered, I literally can't take in any information from it. It's like beating my head against a wall. Horrible design, IMHO. -- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 15, 2007 Report Share Posted June 15, 2007 Hi Steph, this is the best i can find i am afraid. What is the Difference Between T3 and Free T3? Triiodothyronine (T3) is a thyroid hormone that circulates in blood almost completely bound (]99.5%) to carrier proteins. The main transport protein is thyroxine-binding globulin (TBG). However, only the free (unbound) portion of triiodothyronine (free T3) is believed to be responsible for the biological action. Furthermore, the concentrations of the carrier proteins are altered in many clinical conditions, such as pregnancy. In normal thyroid function, as the concentrations of the carrier proteins changes, the total triiodothyronine level also changes, so that the free triiodothyronine concentration remains constant. (In an abnormally functioning thyroid, this is not necessarily so). Measurements of free triiodothyronine (Free T3) concentrations, therefore, correlate more reliably with your clinical status than total triiodothyronine (T3) levels. For example, the increase in total triiodothyronine levels associated with pregnancy, oral contraceptives and estrogen therapy result in higher total T3 levels while the free T3 concentration remains unchanged (in normal individuals). The Free T3 (FT3) Test So what is normal? When specimens are sent to Quest, normal is 230-420 pg/dL. If you are lower than 230 or above 420, you are " abnormal " . That doesn't tell the whole story, however. There is a difference between " normal " and " optimal " . Someone can be " low normal " with a Free T3 of 231 and still feel crummy. Some of my patients, have many hypothyroid symptoms, but have normal lab tests. When they have " low normal " values, I often will empirically try thyroid medication by starting low and going slow. If my patients feel better with medication, I interpret this situation as one where the laboratory tests do not tell the whole story, and that in the future I would make medication adjustments based upon their symptoms and physical exam. If they feel worse with less thyroid medication (such as gaining weight, being more fatigued), I give them more. If they feel like they are getting too much thyroid medication (heart palpitations, anxiety), I give them less. As an aside – giving thyroid hormone to patients who are not truly hypothyroid does not cause these patients to lose weight. They wind up only getting the side effects (such as palpitations), but no benefits (there will be no weight loss if thyroid is not the true problem). It is important to realize that if a patient has thyroid antibodies, all bets are off. All thyroid blood tests from that point on are thrown off, including the Free T3. In that case, one definitely has to go by symptoms to decide the correct level of thyroid medication. Please see my article Understanding Thyroid Lab Tests for a more complete description of why laboratory tests can be thrown off by these antibodies. ABOUT KENNETH WOLINER, MD Dr. Woliner is a board-certified family physician in private practice in Boca Raton. Though he often recommends vitamin supplements, he does not sell them due to conflict of interest concerns. He can be reached at Holistic Family Medicine, 2499 Glades Road #106A, Boca Raton, FL 33431; . E-mail: knw6@... Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 15, 2007 Report Share Posted June 15, 2007 Thanks, . Yes, this stuff is easy to find, and I understand that the frees are most relevant to treatment. But I'm curious whether one can get any useful information from the ratio of free to total (both T3 and T4). Also wondering whether it matters if free and total are at different places in their ranges (like free is halfway in its range, but total is at the top of its range). -- > > Hi Steph, this is the best i can find i am afraid. > > What is the Difference Between T3 and Free T3? > > Triiodothyronine (T3) is a thyroid hormone that circulates in blood > almost completely bound (]99.5%) to carrier proteins. The main > transport protein is thyroxine-binding globulin (TBG). However, only > the free (unbound) portion of triiodothyronine (free T3) is believed > to be responsible for the biological action. Furthermore, the > concentrations of the carrier proteins are altered in many clinical > conditions, such as pregnancy. > > In normal thyroid function, as the concentrations of the carrier > proteins changes, the total triiodothyronine level also changes, so > that the free triiodothyronine concentration remains constant. (In an > abnormally functioning thyroid, this is not necessarily so). > Measurements of free triiodothyronine (Free T3) concentrations, > therefore, correlate more reliably with your clinical status than > total triiodothyronine (T3) levels. > > For example, the increase in total triiodothyronine levels associated > with pregnancy, oral contraceptives and estrogen therapy result in > higher total T3 levels while the free T3 concentration remains > unchanged (in normal individuals). > > The Free T3 (FT3) Test > So what is normal? When specimens are sent to Quest, normal is 230-420 > pg/dL. If you are lower than 230 or above 420, you are " abnormal " . > That doesn't tell the whole story, however. There is a difference > between " normal " and " optimal " . Someone can be " low normal " with a > Free T3 of 231 and still feel crummy. > > Some of my patients, have many hypothyroid symptoms, but have normal > lab tests. When they have " low normal " values, I often will > empirically try thyroid medication by starting low and going slow. If > my patients feel better with medication, I interpret this situation as > one where the laboratory tests do not tell the whole story, and that > in the future I would make medication adjustments based upon their > symptoms and physical exam. > > If they feel worse with less thyroid medication (such as gaining > weight, being more fatigued), I give them more. If they feel like they > are getting too much thyroid medication (heart palpitations, anxiety), > I give them less. As an aside – giving thyroid hormone to patients who > are not truly hypothyroid does not cause these patients to lose > weight. They wind up only getting the side effects (such as > palpitations), but no benefits (there will be no weight loss if > thyroid is not the true problem). > > It is important to realize that if a patient has thyroid antibodies, > all bets are off. All thyroid blood tests from that point on are > thrown off, including the Free T3. In that case, one definitely has to > go by symptoms to decide the correct level of thyroid medication. > Please see my article Understanding Thyroid Lab Tests for a more > complete description of why laboratory tests can be thrown off by > these antibodies. > > ABOUT KENNETH WOLINER, MD > > Dr. Woliner is a board-certified family physician in private > practice in Boca Raton. Though he often recommends vitamin > supplements, he does not sell them due to conflict of interest > concerns. He can be reached at Holistic Family Medicine, 2499 Glades > Road #106A, Boca Raton, FL 33431; . E-mail: knw6@... > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 15, 2007 Report Share Posted June 15, 2007 >But I'm curious whether one can get any useful information from the >ratio of free to total (both T3 and T4). Also wondering whether it >matters if free and total are at different places in their ranges >(like free is halfway in its range, but total is at the top of its >range). >-- Hi , To get the most information about of your tests you must use Dr Rind's Thyroid scale to interpret your tests . http://www.drrind.com/thyroidscale.asp When you plot it on a graph it give valuable information about what is going on. You have to use TSH, fT4 and fT3 to get a valuable idea. Dean Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 15, 2007 Report Share Posted June 15, 2007 ----- Original Message ----- From: But I'm curious whether one can get any useful information from the ratio of free to total (both T3 and T4). Also wondering whether it matters if free and total are at different places in their ranges (like free is halfway in its range, but total is at the top of its range). << Quote Link to comment Share on other sites More sharing options...
Guest guest Posted June 15, 2007 Report Share Posted June 15, 2007 Hi Steph I just think it seems that the Total T4 and T3 are so variable its a worthless test, therefore the ratios to the Free T4 and T3 would therefore be worthless as well. That what i understand of it anyway. Russ > > > > Hi Steph, this is the best i can find i am afraid. > > > > What is the Difference Between T3 and Free T3? > > > > Triiodothyronine (T3) is a thyroid hormone that circulates in blood > > almost completely bound (]99.5%) to carrier proteins. The main > > transport protein is thyroxine-binding globulin (TBG). However, only > > the free (unbound) portion of triiodothyronine (free T3) is believed > > to be responsible for the biological action. Furthermore, the > > concentrations of the carrier proteins are altered in many clinical > > conditions, such as pregnancy. > > > > In normal thyroid function, as the concentrations of the carrier > > proteins changes, the total triiodothyronine level also changes, so > > that the free triiodothyronine concentration remains constant. (In an > > abnormally functioning thyroid, this is not necessarily so). > > Measurements of free triiodothyronine (Free T3) concentrations, > > therefore, correlate more reliably with your clinical status than > > total triiodothyronine (T3) levels. > > > > For example, the increase in total triiodothyronine levels associated > > with pregnancy, oral contraceptives and estrogen therapy result in > > higher total T3 levels while the free T3 concentration remains > > unchanged (in normal individuals). > > > > The Free T3 (FT3) Test > > So what is normal? When specimens are sent to Quest, normal is 230-420 > > pg/dL. If you are lower than 230 or above 420, you are " abnormal " . > > That doesn't tell the whole story, however. There is a difference > > between " normal " and " optimal " . Someone can be " low normal " with a > > Free T3 of 231 and still feel crummy. > > > > Some of my patients, have many hypothyroid symptoms, but have normal > > lab tests. When they have " low normal " values, I often will > > empirically try thyroid medication by starting low and going slow. If > > my patients feel better with medication, I interpret this situation as > > one where the laboratory tests do not tell the whole story, and that > > in the future I would make medication adjustments based upon their > > symptoms and physical exam. > > > > If they feel worse with less thyroid medication (such as gaining > > weight, being more fatigued), I give them more. If they feel like they > > are getting too much thyroid medication (heart palpitations, anxiety), > > I give them less. As an aside – giving thyroid hormone to patients who > > are not truly hypothyroid does not cause these patients to lose > > weight. They wind up only getting the side effects (such as > > palpitations), but no benefits (there will be no weight loss if > > thyroid is not the true problem). > > > > It is important to realize that if a patient has thyroid antibodies, > > all bets are off. All thyroid blood tests from that point on are > > thrown off, including the Free T3. In that case, one definitely has to > > go by symptoms to decide the correct level of thyroid medication. > > Please see my article Understanding Thyroid Lab Tests for a more > > complete description of why laboratory tests can be thrown off by > > these antibodies. > > > > ABOUT KENNETH WOLINER, MD > > > > Dr. Woliner is a board-certified family physician in private > > practice in Boca Raton. Though he often recommends vitamin > > supplements, he does not sell them due to conflict of interest > > concerns. He can be reached at Holistic Family Medicine, 2499 Glades > > Road #106A, Boca Raton, FL 33431; . E-mail: knw6@ > > > Quote Link to comment Share on other sites More sharing options...
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