Thyrotropin (TSH) And Thyroglobulin (Tg) Measurements

Question 1

What are the tumor-marker tests for differentiated thyroid cancer?

Answer 1

• Thyroglobulin (Tg)

- Tg antibodies (TgAb)

Question 2

What is the TSH range - NHANES population range?

Answer 2

0.4 - 4.1 mIU/L

Question 3

What four things influence the upper limit of TSH?

Answer 3

• Age
• Ethnicity
• Reproductive status
• BMI

Question 4

What is the TSH target for patients less than 70 years?

Answer 4

0.4 - 4 mIU/L

Question 5

What is the TSH target for patients more than 70 years?

Answer 5

4 - 6 mIU/L

Question 6

How much is individual TSH variability?

Answer 6

0.5 mIU/L over time

Question 7

Individual change of variability of ____ or more is considered significant.

Answer 7

0.75 mIU/L

Question 8

TSH targets (mIU/L):

Levothyroxine replacement?

Answer 8

0.4 - 4.1

Question 9

TSH targets (mIU/L):

Pre-conception?

Answer 9

0.3 - 2.5

Question 10

TSH targets (mIU/L):

Pregnancy (1st trimester)?

Answer 10

0.01 - 2.5

Question 11

TSH targets (mIU/L):

Pregnancy (2nd and 3rd trimester)?

Answer 11

Upper limit: 3

Question 12

TSH targets (mIU/L):

Elderly patients > 70 years?

Answer 12

Upper limit: 7.5

Question 13

TSH targets (mIU/L):

Obese patients (BMI > 35)

Answer 13

Upper limit: ~ 6

Question 14

TSH targets (mIU/L)

Thyroid cancer?

Question 15

TSH targets (mIU/L):

Non-thyroidal illness - hospitalized patients.

Answer 15

0.05 - 10

Question 16

Which antibody is a primary marker for autoimmune thyroid disease?

Answer 16

TPOAb

Question 17

Is TPOAb a risk factor for drug induced thyroid dysfunction?

Answer 17

Yes

Question 18

Is TPOAb a risk factor for maternal complications?

Answer 18

Yes

Question 19

Name five drugs that can cause thyroid dysfunction.

Answer 19

• Interferon-alpha
• Interleukin-2
• Lithium
• Iodine (contrast)
• Amiodarone

Question 20

What is the ratio of total T3 to total T4 in Graves’ disease?

Answer 20

> 20:1

Question 21

What does pregnancy do to TSH?

Answer 21

Lowers it

Question 22

What does hCG do to TSH?

Answer 22

Suppresses it

Question 23

Why is TSH kept in the lower range of normal during pregnancy?

Answer 23

Because miscarriage risk increases especially when TPOAb detected.

Question 24

When no TPOAb is detected, then miscarriage risk is increased above a TSH of ____ mIU/L?

Answer 24

~ 5

Question 25

When TPOAb is detected, then miscarriage risk is increased above a TSH of ____ mIU/L?

Answer 25

2.5

Question 26

For hypothyroid patients taking levothyroxine it is recommended to increase the dose by ____ % by 4 - 6 weeks of gestation.

Answer 26

30% or more

Question 27

Does subclinical hyperthyroidism have adverse effects on mother or fetus?

Answer 27

No

Question 28

Does free T4 help distinguish between hyperemesis gravidarum and pre-existing hyperthyroidism?

Answer 28

Yes

Question 29

What is HAMA?

Answer 29

Human anti-mouse antibodies

Question 30

What do TgAb do the TG readings?

Answer 30

Interfere

Question 31

What should be followed when thyroglobulin antibodies are positive?

Answer 31

TgAb concentration serves as a surrogate tumor-marker.

Question 32

Which is preferable... Free T3 or total T3?

Answer 32

Total T3