Interpreting Thyroid Labs

Common symptoms reported

• feeling of fullness in throat 
• voice changes
• painless thyroid enlargement
• changes in energy levels
• heat/cold intolerance
• skin changes 
• bowel changes
• mood changes
• menstrual irregularities 
• goiter or thyroid nodule history 

Labs 

• TSH with reflex to Free T4 (preferred) 
• "full" thyroid panel: TSH, free T4, Total T3 (pt requests often)
• TPO antibodies- order if you are evaluating for Hashimoto's Disease 
  • not routinely measured
  • can help predict the likelihood of progression to permanent overt hypothyroidism in patients with subclinical hypothyroidism (elevated TPO antibodies but normal TSH)
• Note* if pt takes a biotin supplement, hold 2 days prior to labs 

Interpreting Thyroid Labs

* Inverse relationship. So if TSH is high think hypothyroid. If TSH is low think hyperthyroid. 

• TSH is normal- no further testing needed 
• TSH elevated > add T4 to determine degree of hypothyroidism 
  • T4 normal = subclinical, recheck in 3 months 
• TSH low > add T4 and T3 to determine degree of hyperthyroidism 

*Treating subclinical hypothyroidism is controversial. I typically talk to patient about it and consider tx if TSH is >10

Come back weekly for new blog posts that can be helpful in practice. I'd love to connect- email me at [email protected] or DM me on social! 

Would you benefit from an experienced NP as a mentor to go over lab results with you, talk about difficult cases, or just ask questions/vent? Check out my 1:1 mentor program here and email me at [email protected] to set up a free 15 minute phone call to discuss further.

 Check out all the other blog posts here.