THYROID STIMULATING IMMUNOGLOBULINS

General Information

HLAB/HOL Code: LATS
UPHSM LIS Test #: 663
Schedule: Monday through Saturday; 4 p.m.
Testing Time: 2 days
Testing Lab: Mayo Labs

Specimen Info
Only 1 specimen type required, unless otherwise specified

Volume: 0.5 mL
Temperature: Refrigerated
Tube Type: 1 Red Top or SST
Collection Info:

Specimen Acceptability

Reject Due To

Hemolysis
Mild OK; Gross reject

Lipemia
Mild OK; Gross OK

Icterus
Mild OK; Gross OK

Methods

Immunoassay

Clinical Utilities

Thyroid stimulating immunoglobulins (TSI) can engage the TSH receptors resulting in hyperthyroidism in Graves' disease patients.  TSI levels can be useful in monitoring the clinical outcome of Graves' disease as well as assessing the potential for hyperthyroidism from maternal-fetal transfer.  TSI results greater than or equal to (>=) 140% of the Reference Control are considered positive.
NOTE: A serum TSH level greater than 350 micro-International Units/mL can interfere with the TSI bioassay and potentially give false positive results.
Patients who are pregnant and are suspected of having hyperthyroidism should have both a TSI and human Chorionic Gonadotropin (hCG) tests measured.  A serum hCG level greater than 40,625 mIU/mL can interfere with the TSI bioassay and may give false negative results.  In these patients it is recommended that a second TSI is obtained when the hCG concentration falls below 40,625 mIU/mL (usually after approx 20-weeks gestation).

CPT Codes

84445

* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding
is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Reference Range

<140 % baseline