Possible Subclinical Hypothyroidism?

[dcjmiller33]

I am really confused by my lab results. I have been having symptoms of hypothyroidism (cold intolerance, mood swings, fatique, muscle aches). So my doctor ran a TSH test. The results were the following:

29 Jan 2010   TSH Sensitive:    4.800  H   (0.465-4.680)  mIU/L
09 Jul 2009     FT4              :     0.80        (0.79-2.35)     ng/dL

He said this could be a sign of hypothyroidism, so he decided to retest. The results were the following:

03 Feb 2010   Thyroid AutoAB:    Negative
                     TSH Sensitive:     3.150      (0.465-4.680)  mIU/L
                      FT4              :     1.02        (0.79-2.35)     ng/dL
                      T3                :     1.320      (0.970-1.690)  ng/mL

He decided that my thyroid was normal based on the lab results. My question is why would my TSH be high one week, then just a week later, be back in the normal range?  I am still having hypo-like symptoms.

What should be my next step?

[dcjmiller33]

I went for my follow up labs around 2pm in the afternoon.  I found it odd that the doctor would do follow up labs that close to the original labs.

[compnet]

Just curious -- what time of day did you go for each of the tests?

[Mark Lupo, M.D.]

TSH is slighly high - this mild fluctuation is not unusual.
This may be mild subclinical hypothyroidism due to hashimotos (w/ negative antibodies -- occurs in 10-15% of Hashimoto's patients)
A thyroid ultrasound may help complete the work-up, particularly with the slightly high TSH.