A person must keep several things in mind when being tested for thyroid problems. In certain cases, having symptoms can be more accurate than a negative blood test.
It is entirely possible to have thyroid problems despite having a blood test that comes back negative.
People who have symptoms of thyroid problems but have gotten a negative result from their blood test should be tested for antibodies. An antibodies test can detect problems that may otherwise go unnoticed by a standard blood test.
If your blood test for thyroid problems comes back negative, consider consulting another physician for a second round of testing just to make sure.
The "reference range" of a testing facility is the measure of a person's test results in relation to "normal" readings. What is considered "normal" in one testing facility may not be looked at the same way in another. If you still suspect you have a problem, have a blood test taken with another testing facility.
Symptoms of thyroid problems and disease include consistent feelings of exhaustion, constipation, pain and uncomfortableness in the wrists and hands, a loss of appetite, and weight gain. If you continue to experience these symptoms even after a negative blood test, to consult your doctor.