July 4, 2007
Thyroid
Question from Willis, Texas, USA:
My soon-to-be 16-year-old son has had type 1 since December 1997. He had laboratory tests done five days ago. His A1c was 6.0, T4 was 0.67 and TSH was 0.77. The T4 value has me extremely concerned. The laboratory’s range for T4 is 0.77 – 1.9. The doctor said everything looked good, including the T4 level. I am not comfortable with the T4 value being “below” the range limit. My son is in the middle of teen years and growing and I don’t want anything to make him ill that we don’t know about. Is this T4 value “really” okay or should we pursue this issue further?
Answer:
I suspect you had a free T4 level and not a total T4 level from the normal range you reported. You should ask your physicians why the low free T4 is okay. The TSH is usually a more reliable value, but you are also correct that both should be normal unless your son is taking some other medication that might interfere with the assay itself.
SB
