Page 1376 - Saunders Comprehensive Review For NCLEX-RN

C. T and T resin uptake test
3
4
1. Blood tests are used to diagnose thyroid disorders.
2. T and T regulate thyroid-stimulating hormone.
4
3
3. Normal values (normal findings vary between
laboratory settings)
a. Triiodothyronine, total T : 110.4 to 337.7
3
ng/dL (1.7 to 5.2 pmol/L)
b. Thyroxine, total T : 5 to 12 mcg/dL (64
4
to 154 nmol/L)
c. Thyroxine, free (FT ): 0.8 to 2.8 ng/dL
4
(10 to 36 pmol/L)
4. The T level is elevated in hyperthyroidism and
4
decreased in hypothyroidism.

D. Thyroid-stimulating hormone

1. Blood test is used to differentiate the diagnosis of
primary hypothyroidism.
2. Normal value is 2 to 10 mclU/mL (2 to 10 mlU/L).
3. Elevated values indicate primary hypothyroidism.
4. Decreased values indicate hyperthyroidism or
secondary hypothyroidism.
E. Thyroid scan
1. A thyroid scan is performed to identify nodules or
growths in the thyroid gland.
2. A radioisotope of iodine or technetium is administered
before scanning the thyroid gland.

3. Reassure the client that the level of radioactive

medication is not dangerous to self or others.
4. Determine whether the client has received
radiographic contrast agents within the past 3
months, because these may invalidate the scan.

5. Check with the primary health care provider

(PHCP) regarding discontinuing medications
containing iodine for 14 days before the test and the
need to discontinue thyroid medication before the
test.
6. Instruct the client to maintain NPO (nothing by
mouth) status after midnight on the day before the
test; if iodine is used, the client will fast for an
additional 45 minutes after ingestion of the oral
isotope and the scan will be performed in 24 hours.
7. If technetium is used, it is administered by the
intravenous (IV) route 30 minutes before the scan.

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