Thyroid Tests

Question 1

What is tested in thyroid function test?

Answer 1

1. TSH * 1st key test that needs to be done
2. Free T3
3. Free T4

Question 2

What is tested in thyroid function test?

Answer 2

1. TSH
2. Free T3
3. Free T4

Question 3

What thyroid autoantibodies can be tested and what do they suggest?

Answer 3

Hashimotos:
Anti-TPO (thyroid peroxidase)

Graves:
Anti TSH receptor*
Anti- TPO
Anti-thyroglobulin

Question 4

What thyroid autoantibodies can be tested and what do they suggest?

Answer 4

Hashimotos:
Anti-TPO (thyroid peroxidase)

Graves:
Anti TSH receptor*
Anti- TPO
Anti-thyroglobulin

Question 5

What is a thyroid nodule?

Answer 5

Nodule detected in thyroid > 2cm

Question 6

List all thyroid tests

Answer 6

TSH
T3
T4
Auto antibodies
FNA
Thyroid Scintigraphy (isotope scan)
Thyroid US
CT scan

Question 7

List all thyroid tests

Answer 7

TSH
T3
T4
Auto antibodies
FNA
Thyroid Scintigraphy (isotope scan)
Thyroid US
CT scan

Question 8

If TSH is low, what is the next Ix test?

Answer 8

Thyroid scintigraphy (isotope uptake scan) to determine if 
Hyper-functioning: less likely to be malignant
Hypofunctioning: cyst, colloid nodule, haemorrhage; carcinoma usually non functioning

Question 9

Why is important to investigate thyroid incidentalomas?

Answer 9

There is a 5-15% risk of cancer

Question 10

What is an thyroid incedentaloma?

Answer 10

Non palpable nodule (where a nodule is > 2cm)

Question 11

If TSH is high, what is the next Ix test?

Answer 11

Ultrasound: refer to increase predictors of nodules being cancerous based on features picked up on US

Question 12

When should we FNA biopsy a thyroid nodule?

Answer 12

Depends on features picked up by 1. ultrasound and 2. size of nodule

FNA if:
> 1cm + High suspicion on US: irregular margin, hyperechoic, taller than wider, calcification

> 2cm + low suspicion on US

No biopsy if benign - pure cyst

Question 13

When should we FNA biopsy a thyroid nodule?

Answer 13

Depends on features picked up by 1. ultrasound and 2. size of nodule

FNA if:
> 1cm + High suspicion on US: irregular margin, hyperechoic, taller than wider, calcification

> 2cm + low suspicion on US

No biopsy if benign - pure cyst

Question 14

When is a CT scan required in thyroid Ix?

Answer 14

Used to determine if there is significant compression of the neck from a large multinodular goitre with retrosternal extension