TSH w/Reflex to FT4 Don't Understand the results

[Glorybe2006]

The doctor ordered the TSH w/Reflex to FT4 but never said anything further about it.  Today I saw the results and am confused.  The Range by Quest Labs is 0.40 - 4.50.  My results is 0.73.  Is this bad or good?  Do I need to follow up about this?

[Barb135]

Oh dear; it's too bad labs won't quit running that test...sigh...
Since you say your doctor didn't say anything further after ordering the test, I'm going to assume s/he didn't tell you what it means either, so I'll explain that first.

TSH is a pituitary hormone that stands for Thyroid Stimulating Hormone. It stimulates the thyroid to produce the hormones T4 and T3.  T4 is considered a "storage" or pro-hormone and must be converted to T3 prior to use.  T3 is the hormone that's used by nearly ever cells in your body.  Most of the T4 and T3 we have are bound by proteins and can't be used, therefore, for testing purposes, we test for Free T4 and Free T3 so we can see how much of the active hormones we have available for, either conversion in the case of T4 or for use, in the case of T3.  

When a doctor orders TSH w/reflex to Free T4, they are telling the lab to analyze TSH and if that result is normal to do nothing else.  If the TSH is abnormal, the lab is to analyze Free T4.  

In your case, the reference range for TSH is 0.40 - 4.50 and your result is 0.73, which is greater than 0.40 and less than 4.50 so it's within the reference or "normal".  

This is an outdated test and typically, doctors that order it are not savvy about thyroid conditions - either diagnosing them or treating them.  

It would be helpful to know why your doctor ordered this test.  Do you have symptoms of a thyroid condition?  If so, please tell us what symptoms and we can go from there...

[Glorybe2006]

Hi Barb135!  Thank you so much for taking the time to respond.  The ordering physician is my pulmonologist.  I struggle with very severe bronchitis and explained that I had no energy and was always sleepy but when I tried to sleep I couldn't. No other reason.  He prescribed Modafinil and that helped a lot.  Thanks again for your information.  I won't worry.  

[Barb135]

Breathing issues can be caused by thyroid conditions AND they can cause fatigue because you aren't getting enough oxygen to your cells.  It's not unusual to be unable to sleep even though one is fatigued.  It's also understandable that you'd not be able to sleep if you can't breathe well, so if your breathing is improved, hopefully your sleep will improve, which in turn would improve your energy levels, along with oxygen levels.

If you do find that you need thyroid testing in the future, please be sure that your doctor orders the actual thyroid hormone tests, Free T4 and Free T3, along with the TSH test, so you get a full picture of what's going on.

Good luck and if we can help you further, please let us know...