So, David's Dr. is mystified about his condition. The underlying problem appears to be a particular hemoglobin deficiency for which they don't know the cause. It would appear everything else re blood tests are OK but the Dr. is keeping David on the Synthroid.???????? A bone marrow test will be performed when David goes in to have his gallbladder removed. David says he feels an overwhelming fatigue, and has to "steel" himself to get up and get going.