Thyroid-stimulating Hormone (TSH)
Also known as: Third-generation TSH, Thyrotropin
Use
Thyroid function test. Investigation of low thyroxine (T4) result; the differential diagnosis of primary hypothyroidism from normal, and the differential diagnosis of primary hypothyroidism from pituitary/hypothalamic hypothyroidism. TSH is high in primary hypothyroidism. Low TSH occurs in hyperthyroidism. Evaluation of therapy in hypothyroid patients receiving various thyroid hormone preparations: Low values are found in states of excessive thyroid replacement. Normal result on a sensitive TSH assay is acceptable evidence of adequate thyroid replacement.
Special Instructions
This test may exhibit interference when the sample is collected from an individual consuming a supplement with high doses of biotin. Patients should stop biotin consumption at least 72 hours before sample collection. It is advised to discuss biotin supplementation with patients prior to the test.
Limitations
TSH results can be influenced by antibovine TSH antibodies with some assay techniques, glucocorticoids, dopamine, and severe illness. These factors contribute to potential limitations in the accuracy of TSH levels, even with new sensitive assays. Additional considerations include interference from certain medications and the complexity of accurately reflecting thyroid status due to various pathological conditions such as nonthyroidal illness, thyrotropin-producing tumors, and psychiatric disorders.
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 11580-8
- 11580-8
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.7 mL
Container
Red-top tube, gel-barrier tube or green-top (lithium heparin) tube. Do not use oxalate, EDTA or citrate plasma.
Collection Instructions
If a red-top tube or plasma is used, transfer separated serum or plasma to a plastic transport tube.
Patient Preparation
Patients should stop biotin consumption at least 72 hours prior to collection.
Storage Instructions
Room temperature
Causes for Rejection
Citrate plasma specimen; improper labeling
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |