Thyroid Function Tests

Question 1

What tests would you expect if hyperthyroidism was suspected?

Answer 1

Raised T3 and T4 Low TSH

Question 2

What tests would you expect if hypothyroidism was suspected?

Answer 2

Low T3 and T4 Raised TSH

Question 3

When is Thyroxine binding globulin raised?

Answer 3

IN pregnancy Oestrogen therapy (HRT, oral contraceptives) Hepatitis

Question 4

When is Thyroxine binding globulin reduced?

Answer 4

Nephrotic syndrome Malnutrition Drugs - phenytoin, corticosteroids, androgens Chronic liver disease Acromegaly

Question 5

What does it mean when thyroid peroxidase antibodies are high?

Answer 5

The presence of TPO antibodies in your blood suggests that the cause of thyroid disease is an autoimmune disorder, such as Hashimoto’s disease or Graves’ disease. In autoimmune disorders, your immune system makes antibodies that mistakenly attack normal tissue.

Question 6

What does it mean when TSH receptor antibodies are high?

Answer 6

High in Graves’ disease Useful for pregnancy

Question 7

When would serum thyroglobulin be investigated?

Answer 7

Useful in monitoring the treatment of carcinoma and in detection of factitious hyperthyroidism, where it is low

Question 8

When would an ultrasound be useful in investigating thyroid pathologies?

Question 9

When are isotope scans used in thyroid pathologies?

Question 10

When is surgery indicated in goitre?

Answer 10

• Rapid growth
• Compression signs
• Dominant nodule on scintigraphy
• Nodule >3cm

Question 11

What kind of patients would you screen for thyroid function abnormalities?

Question 12

What is sick euthyroidism?

Answer 12

• When TFTs become deranged due to any systemic illness
• The typical pattern is for everything to be low
• The test should be repeated after recovery

Question 13

Diagnose each hormone profile in the table below:

Answer 13