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23190 Thyrotropin Receptor Antibody (THYRO)

Thyrotropin Receptor Antibody (THYRO)
Test Code: THRECSO
Synonyms/Keywords
​Ref Lab Code: 81797, Antibodies to TSH receptor, Inhibitory Immunoglobulin, Long-Acting Thyroid Stimulator (LATS), TBII (TSH-Binding Inhibiting Immunoglobulin), Thyroid-Stimulating Hormone Receptor (TSH Receptor) Antibody, TRAb (Thyrotropin Receptor Antibody), TSH (Thyroid-Stimulating Hormone) Receptor Binding, TSH Binding Inhibition Index, TSH Receptor (Thyroid-Stimulating Hormone Receptor) Antibody, TSH-Binding Inhibiting Immunoglobulin (TBII), Graves Disease
Useful For
​Recommended first-line test for detection of thyrotropin receptor (TSHR) antibodies, and used in the following situations:
-Differential diagnosis of etiology of thyrotoxicosis in patients with  ambiguous clinical findings and/or contraindicated (eg, pregnant or breast-feeding) or nondiagnostic thyroid radioisotope scans
-Diagnosis of clinically suspected Graves disease (eg, extrathyroidal manifestation of Graves disease include endocrine exophthalmos, pretibial myxedema, thyroid acropachy) in patients with normal thyroid function tests
-Determining the risk of neonatal thyrotoxicosis in a fetus of a pregnant female with active or past active Graves disease
-Differential diagnosis of gestational thyrotoxicosis versus first trimester manifestation or recurrence of Graves disease
-Assessing the risk of Graves disease relapse after antithyroid drug treatment
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​Serum Red Top Tube (RTT)​ Serum Separator Tube (SST)​ 1 mL​ 0.75 mL​
Specimen Stability Information
Specimen Type Temperature Time
Serum​ Refrigerated (preferred)​ 7 days​
Frozen ​ 30 days​
Rejection Criteria
Gross hemolysis
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories
Monday through Saturday ​
1 day / same day​
Electrochemiluminescence Immunoassay​
Reference Lab
Test Information
​Recommended first-line test for detection of thyrotropin receptor (TSHR) antibodies, and used in the following situations:
1) Differential diagnosis of etiology of thyrotoxicosis in patients with ambiguous clinical findings and/or contraindicated (i.e. pregnant or breast-feeding) or nondiagnostic thyroid radioisotope scans.
2) Diagnosis of clinically suspected Graves disease (i.e. extrathyroidal manifestation of Graves disease include endocrine exophthalmos, pretibial myxedema, thyroid acropachy) in patients with normal thyroid function tests.
3) Determining the risk of neonatal thyrotoxicosis in a fetus of a pregnant female with active or past active Graves disease.
4) Differential diagnosis of gestational thyrotoxicosis versus first trimester manifestation or recurrence of Graves disease.
5) Assessing the risk of Graves disease relaspse after antithyroid drug treatment.
Reference Range Information
<= 1.75 IU/L
Interpretation
​The sensitivity and specificity of an elevated thyrotropin receptor antibody (TRAb) test for Graves disease diagnosis depends on whether patients have disease treated with antithyroid drugs or clinically active, untreated disease. Based on a study that included specimens from 436 apparently healthy individuals, 210 patients with thyroid diseases without diagnosis of Graves disease, and 102 patients with untreated Graves disease, a decision limit of 1.75 IU/L showed a sensitivity of 97% and a specificity of 99% for detection of Graves disease.(1) In healthy individuals and in patients with thyroid disease without diagnosis of Graves disease, the upper limit of anti-thyrotropin receptor (anti-TSHR) values are 1.22 IU/L and 1.58 IU/L, respectively (97.5th percentiles).(1) A Mayo study of 115 patients, including 42 patients with Graves disease, showed a sensitivity of 95% and a specificity of 97% for detection of Graves disease at a decision limit of 1.75 IU/L.
 
Assessment of TRAb status is particularly relevant in women who have undergone thyroid ablative therapy or are on active antithyroid treatment and, therefore, no longer display biochemical or clinical evidence of thyrotoxicosis. Significant neonatal thyrotoxicosis is likely if a pregnant woman with a history of Graves disease has TRAb concentrations of >3.25 IU/L during the last trimester, regardless of her clinical remission status. Lesser elevations are only occasionally associated with neonatal thyrotoxicosis. Gestational thyrotoxicosis, which is believed to be due to a combination of human chorionic gonadotropin cross-reactivity on the TSHR and transient changes in thyroid hormone protein binding, is only very rarely associated with an elevated TRAb test. Finding an elevated TRAb test in this setting suggests usually underlying Graves disease.
 
An elevated TRAb test at the conclusion of a course of antithyroid drug treatment is highly predictive of relapse of Graves disease. However, the converse, a normal TRAb test, is not predictive of prolonged remission.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83520
Synonyms/Keywords
​Ref Lab Code: 81797, Antibodies to TSH receptor, Inhibitory Immunoglobulin, Long-Acting Thyroid Stimulator (LATS), TBII (TSH-Binding Inhibiting Immunoglobulin), Thyroid-Stimulating Hormone Receptor (TSH Receptor) Antibody, TRAb (Thyrotropin Receptor Antibody), TSH (Thyroid-Stimulating Hormone) Receptor Binding, TSH Binding Inhibition Index, TSH Receptor (Thyroid-Stimulating Hormone Receptor) Antibody, TSH-Binding Inhibiting Immunoglobulin (TBII), Graves Disease
Ordering Applications
Ordering Application Description
​Centricity ​Thyrotropin Receptor Ab
​Cerner ​Thyrotropin Receptor Antibody (81797)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​Serum Red Top Tube (RTT)​ Serum Separator Tube (SST)​ 1 mL​ 0.75 mL​
Specimen Stability Information
Specimen Type Temperature Time
Serum​ Refrigerated (preferred)​ 7 days​
Frozen ​ 30 days​
Rejection Criteria
Gross hemolysis
Useful For
​Recommended first-line test for detection of thyrotropin receptor (TSHR) antibodies, and used in the following situations:
-Differential diagnosis of etiology of thyrotoxicosis in patients with  ambiguous clinical findings and/or contraindicated (eg, pregnant or breast-feeding) or nondiagnostic thyroid radioisotope scans
-Diagnosis of clinically suspected Graves disease (eg, extrathyroidal manifestation of Graves disease include endocrine exophthalmos, pretibial myxedema, thyroid acropachy) in patients with normal thyroid function tests
-Determining the risk of neonatal thyrotoxicosis in a fetus of a pregnant female with active or past active Graves disease
-Differential diagnosis of gestational thyrotoxicosis versus first trimester manifestation or recurrence of Graves disease
-Assessing the risk of Graves disease relapse after antithyroid drug treatment
Reference Range Information
<= 1.75 IU/L
Interpretation
​The sensitivity and specificity of an elevated thyrotropin receptor antibody (TRAb) test for Graves disease diagnosis depends on whether patients have disease treated with antithyroid drugs or clinically active, untreated disease. Based on a study that included specimens from 436 apparently healthy individuals, 210 patients with thyroid diseases without diagnosis of Graves disease, and 102 patients with untreated Graves disease, a decision limit of 1.75 IU/L showed a sensitivity of 97% and a specificity of 99% for detection of Graves disease.(1) In healthy individuals and in patients with thyroid disease without diagnosis of Graves disease, the upper limit of anti-thyrotropin receptor (anti-TSHR) values are 1.22 IU/L and 1.58 IU/L, respectively (97.5th percentiles).(1) A Mayo study of 115 patients, including 42 patients with Graves disease, showed a sensitivity of 95% and a specificity of 97% for detection of Graves disease at a decision limit of 1.75 IU/L.
 
Assessment of TRAb status is particularly relevant in women who have undergone thyroid ablative therapy or are on active antithyroid treatment and, therefore, no longer display biochemical or clinical evidence of thyrotoxicosis. Significant neonatal thyrotoxicosis is likely if a pregnant woman with a history of Graves disease has TRAb concentrations of >3.25 IU/L during the last trimester, regardless of her clinical remission status. Lesser elevations are only occasionally associated with neonatal thyrotoxicosis. Gestational thyrotoxicosis, which is believed to be due to a combination of human chorionic gonadotropin cross-reactivity on the TSHR and transient changes in thyroid hormone protein binding, is only very rarely associated with an elevated TRAb test. Finding an elevated TRAb test in this setting suggests usually underlying Graves disease.
 
An elevated TRAb test at the conclusion of a course of antithyroid drug treatment is highly predictive of relapse of Graves disease. However, the converse, a normal TRAb test, is not predictive of prolonged remission.
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Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories
Monday through Saturday ​
1 day / same day​
Electrochemiluminescence Immunoassay​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83520
For most current information refer to the Marshfield Laboratory online reference manual.