Free T4 and Free T3 should be tested every time she goes in for tests. In addition, TSH will help identify if she has Hashimoto's Thyroiditis. If TSH is high, then two tests should be done to determine if it is Hashi's. Those are Thyroid Peroxidase antibodies and Thyroglobulin Antibodies, shown as TPO ab and TG ab.
Also since hypo patients are so frequently low in Vitamin D, B12 and ferritin, those should be done. When she has test results, if she will post here, along with reference ranges shown on the lab report we will be happy to help interpret and advise further.
Low vitamin D is very common with autoimmune conditions.
She will need to supplement with D3 (available from health food stores), which is best combined with k2. Given that her D was so low (dangerously low), she may need a fairly high dose to get up to middle of normal range.
As an example, I take 15000 IUI/day of D3. My last test, on 10000 IUI I was still below range, which is why I increased to 15000 IUI. I will test again shortly.
Sublingual B12 is available and generally has better absorption than the tablet type.
Have your sister keep searching for a dr, including making sure they know how bad she is feeling. Low in range Ft4 is a problem. So therefore, low dose thyroid replacement is probably indicated if she has a more aggressive dr.
Thank you all so very much for replying. I really appreciate. I will let her know
Dee
When I told my sister to be tested I made sure she requested thyroid antibodies. While her labs were in range (her free T4 low in the range though) she had high thyroid antibodies confirming Hashimoto's thyroiditis. She gained 10 kg but her doctor prescribed her duromine and she lost all her weight but she had recently started to gain weight again. As she has been thin all her life that is her metabolism slowing down due to Hashimoto's. No doctor will give her thyroxine however due to normal levels of TSH, free T4 and free T3.
if test cost is concerning then test at least free t4 and tsh. if need to reduce that too then do free t4 instead of tsh.