The Basics
This is the number of TSH tests done yearly in US.
What is 60 million?
Assays of this free thyroid hormone are most accurate.
What is free T4?
It is always elevated in Hashimoto's thyroiditis
What is a defining characteristic of thyroid peroxidase antibody (TPO-Ab)?
A marker of differentiated thyroid cancers (papillary and follicular)
What is thyrogloulin?
They have higher levels of inactive TSH
Why do people have higher normal TSH levels as they age?
This secretes TRH (thyrotropin releasing hormone).
WHat is the hypothalamus?
This common dietary supplement interferes with tests for TSH and free T4
What is Biotin?
A stimulating antibody found only in Graves disease
What is TSH receptor Antibody (TRAb)?
A marker of medullary thyroid cancer
What is Procalcitonin (or Calcitonin)?
A marker of thyroid autoimmune problems
What is thyroglobulin antibody (Tg-Ab)?
This amounts to about 15% of thyroid hormones.
What is T3 (triiodothyronine)?
This normal physiological state makes thyroid test interpretations challenging.
What is pregnancy?
This is the most common cause of hypothyroidism when iodine is not rare.
What is Hashimoto's thyroiditis?
A Marker of medullary thyroid cancer that is less prone to interference
What is Procalcitonin
THis produces both false positive and false negative assay results for thyroid tests. Specify which test becomes falsely positive and which test falsely negative.
What is Biotin? It gives falsely high results for TSH and falsely low results for free T. EXTRA CREDIT if you can explain the reasons behind this!!
Deiodinases do this.
WHat converts free T4 to free T3?
It is unclear if thyroid level changes due to this condition are helpful, harmful or neutral.
What is pregnancy?
This condition causes both hyperthyroidism and hypothyroidism.
What is Hashimoto's thyroiditis?
This is the active thyroid hormone.
What is free T3?
These provide negative feedback to the hypothalamus and anterior pituitary.
What are thyroid hormones (T3 and T4)?
If there is no assay interference, these labs suggest hypothyroidism due to a pituitary issue.
What is low TSH and low free T4?