<prompt> The Lab investigation of a patient shows T4, TSH Which of the following is the most likely diagnosis:Graves diseaseHashimotos diseasePituitary failureHypothalamic failure  <response>: T4, TSH - suggests primary hypothyroidism Chronic thyroiditis or Hashimotos disease is a common thyroid gland disorder. It can occur at any age, but is most often seen in middle-aged women. It is caused by a reaction of the immune system against the thyroid gland. The disease begins slowly. It may take months or even years for the condition to be detected. Chronic thyroiditis is most common in women and people with a family history of thyroid disease. Laboratory tests to determine thyroid function include: 1. Free T4 test low 2. Serum TSH high 3. T3 low or normal Thyroid autoantibodies: Antithyroid peroxidase pothalamic failure are causes of secondary hypothyroidism with low TSH and T4 Ref: Harrisons 16th Edition, Page 2109 table 