Doctor insights on:
Total Vs Free T4
Thyroid tests: A "free T4" level is a measure of the biologically active amount of thyroid hormone in the blood, circulating "free" (rather than attached to blood proteins). Anti-microsomal or anti-peroxidase antibodies, are antibodies circulating in the blood stream that are associated with having autoimmune thyroid disease. ...Read more
Yes: Total T4 reflects T4 bound to proteins in your blood. Free T4 measures the amount of T4 that is free and not bound so that it can be metabolically active. Thus women taking Estrogens (as in bc pills) have elevated levels of thyroid binding globulin and elevated total t4, but normal free t4. ...Read more
I've been on the same dose of Levothyroxine for 3 years (0.75mcg) & free t4 has always been normal (1.6). Recently, my FT4 was elevated (2.30) Why???
Unsure: If someone has changed the way they take their thyroid medications - if you were taking w/ food and now on empty stomach, if there is a new batch of thyroid meds there can be some variation in potency, less fiber in your diet, lab error, stopping eating soy, herbal supplements, stopping antidepressants or cholesterol meds, taking steroids or being sick --- these can all effect FT4 and TSH levels ...Read more
Every lab ..: Different ranges of normal- so both need to be in normal range of that lab. ...Read more
Thyroid labs: Every medical laboratory has different values for the labs they are doing. Please have your doctor tell you what is the normal range for Free T4 and TSH. If you are in range that's great. If not your doctor has to develop a treatment program for you. Not difficult for the doctor or you. ...Read more
My free T4 test test reads 0.61 ng/dl with the normal value for the lab being 0.8-1.7. Shouldnt I be treated?
Not Necessarily: Your ft4 needs to be assessed when taken into consideration with TSH and other tests. Also, the lab assay for ft4 may be unreliable as in many facilities. Or you might be on other medication interfering in the testing process of ft4. Other tests may be more reliable in assessing thyroid hormone levels if ft4 is persistently low. The direct dialysis method may be helpful. ...Read more
More details needed: The TSH is low suggesting you have too much thyroid. Different labs have diff. normal ranges so hard to comment on the Free T4 without knowing lab's normal range- might be high, might be low and we can't tell! Also we need to know if you are currently taking Eltroxcin and, if so, how much. In general, it would be wiser to ask the doctor who ordered the test. ...Read moreSee 1 more doctor answer
Free T4 is 16.9 pmol/l, TSH 1.08 miul/l gp said all normal. I feel dizzy, and on overdrive.Advise?
High Free T4: The result for free T4 seems quite high to me and could well account for your symptoms. That said, different labs have different reference data so you should ask your doctor to show you the normal range for free t4. ...Read more
Tt in dec. Due to pap. Carc. Thyroglobulin ab doubled since then, and thyroglobulin still under 0.2. Free T4 went from normal to low. Is this normal?
Thyroid cancer: Thyroglobulin is unreliable in the presence of tg antibodies but the antibodies shouldn't go up. More information is needed regarding size of thyroid cancer and spread to determine if you also need radioactive iodine. Make sure your TSH is suppressed. You might need to increase your current thyroid dose to achieve this. Follow your doctor closely and monitor this. Good luck. ...Read moreSee 1 more doctor answer
Something is: Incorrect, as free T4 measurements don't go up that high. If free T4 is above normal and tsp is suppressed you need to be evaluated (and probably treated) for hyperthyroidism. Check w/your doctor and see if there was some sort of clerical error in the free T4 result. ...Read moreSee 1 more doctor answer
Yes,,: These are technically "normal" values with fT4 normal range being 9-18 pmol/L while TSH is about 0.3-3.0 uIU/mL, though this last range can vary. Best of luck. ...Read more
Few possibilities: These labs seem at odds, with TSH suggesting overactive thyroid and ft4 underactive thyroid. Free T4 tests can be inaccurate in some people who have interfering substances present. Another possibility is a tumor in the pituitary secreting too much TSH resulting in thyroid overactivity, and high thyroid hormone levels. This is quite rare, however. Your doctor can help sort this out. ...Read more
Thyroid results: It implies that your thyroid may be sluggish but the numbers are different for each lab so you have to include the normal range for that particular lab to have more meaning. ...Read more