T4 (thyroxine) is converted into T3 at the cellular level in virtually all organs. Intracellular T3 levels regulate pituitary secretion and blood levels of thyroid-stimulating hormone (TSH), as well as the effects of thyroid hormone in multiple organs; a normal TSH indicates an adequate T4 dose. Conversion of T4 to T3 at the cellular level may not be reflected in the T3 level in the blood. Compared to patients with intact thyroid glands, patients with hypothyroidism taking T4 may have higher ...
Once target control is achieved in adults with stable type 2 diabetes and the results of self-glucose monitoring become quite predictable, there is little gained in most individuals from repeatedly confirming. There are many exceptions, such as for acute illness, when new medications are added, when weight fluctuates significantly, when A1c targets drift off course and in individuals who need monitoring to maintain targets. Self-monitoring is beneficial as long as one is learning and adjusting ...
Measurement of insulin either in the fasting state or during an oral glucose tolerance test is not a clinically useful method (and may be costly because of the insulin assay) to estimate insulin sensitivity. The hyperinsulinemic-euglycemic (HIEG) clamp is the gold standard for assessing insulin sensitivity as it is possible to assess tissue specific sensitivity and can be used in all types of populations. This feature is important because a method of standardisation must be developed to control ...
Many of the symptoms attributed to male hypogonadism are commonly seen in normal male aging or in the presence of comorbid conditions. Testosterone therapy has the potential for serious side effects and represents a significant expense. It is therefore important to confirm the clinical suspicion of hypogonadism with biochemical testing. Current guidelines recommend the use of a total testosterone level obtained in the morning. A low level should be confirmed on a different day, again measuring ...
Thyroid ultrasound is used to identify and characterize thyroid nodules, and is not part of the routine evaluation of abnormal thyroid function tests (over- or underactive thyroid function) unless the patient also has a palpably large goitre or a nodular thyroid. Incidentally discovered thyroid nodules on ultrasound are common. Overzealous use of ultrasound will frequently identify nodules, which are unrelated to the abnormal thyroid function, and may divert the clinical evaluation to assess ...