Clinics and Departments

Laboratory Services

Lab Dept:

Serology

Test Name:

ANTITHYROGLOBULIN ANTIBODY

General Information

Lab Order Codes:

ATA

Synonyms:

Thyroglobulin Antibody Screen

CPT Codes:

86800 – Thyroglobulin antibody

Test Includes:

Thyroglobulin antibody screen reported in IU/mL.

Logistics

Test Indications:

Primary use: Identification of potentially unreliable serum Tg measurements in the follow-up of patients with differentiated follicular-cell derived thyroid carcinomas.

Secondary use: As an adjunct to anti-thyrotropin and thryoid-stimulating immunoglobulin measurements in the diagnosis of autoimmune thryoid disease: Hashimoto disease, Postpartum thyroiditis, Neonatal hypothyroidism, Graves disease

Lab Testing Sections:

Serology - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: TGAB)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1 – 3 days, performed Monday - Saturday

Special Instructions:

If Thyroglobulin Tumor Marker, Serum, is desired, DO NOT order this test. See Thyroglobulin Tumor Marker which includes both thyroglobulin and thyroglobulin antibody.

Specimen

Specimen Type:

Blood

Container:

Red top (plain, no gel) tube

Draw Volume:

3 mL (Minimum: 1.5 mL) blood

Processed Volume:

1 mL (Minimum: 0.5 mL) serum

Note: Submission of the minimum volume will not allow for repeat analysis and could result in a QNS (quantity not sufficient) result.

Collection:

Routine venipuncture

Special Processing:

Lab Staff: Centrifuge specimen, remove serum aliquot into a screw-capped round bottom plastic vial. Store and ship at refrigerated temperatures. Forward promptly.

Patient Preparation:

None

Sample Rejection:

Gross hemolysis; mislabeled or unlabeled specimens

Interpretive

Reference Range:

All ages:

<4.0 IU/mL

Critical Values:

N/A

Limitations:

Low titers of thyroid autoantibodies may be observed in the absence of autoimmune or other thyroid diseases and are considered a nonspecific finding. The population prevalence of such nonspecific low-level anti-Tg positivity is higher in females than in males and increases with age in both genders.

Detection of significant titers of anti-Tg or anti-TPO autoantibodies is supportive evidence for a diagnosis of Graves disease in patients with thyrotoxicosis. However, measurement of the pathogenic anti-TSH receptor antibodies by binding assay or bioassay is the preferred method confirming Graves disease in atypical cases and under special circumstances.

Patients with nodular thyroid disease who are anti-thyroid autoantibody positive may have coexisting Hashimoto disease, which can result in a suspicious fine-needle aspiration biopsy diagnosis of follicular or Hurthle cell neoplasia.

Anti-Tg values determined by different methodologies might vary significantly and cannot be directly compared with one another. Some patients might show to be antibody-positive by some methods and antibody-negative by others. Comparing anti-Tg antibody values from different methods might lead to erroneous clinical interpretation.

In patient receiving therapy with high biotin doses (ie, >5 mg/day), no specimen should be drawn until at least 8 hours after the last biotin administration.

Tg concentrations >2,000 ng/mL may lead to falsely elevated anti-Tg concentrations.

Methodology:

Immunoenzymatic Assay

References:

Mayo Medical Laboratories Web Page (June 2013)

Updates:

2/11/2008: Reference range update, previously listed as <1:100
Method update: Previously listed as Gelatin Particle Agglutination
5/3/2010: Updated specimen volumes
1/272011: Due to reagent issues at MML, they are now forwarding this testing to Quest. Note the new reference range, change in preferred draw volume and store/ship temperature.
2/3/2011: Back to refrigerated.
4/12/2011: Testing returned to Mayo. New method, new reference range (previously listed as <20 IU/mL).
10/6/2014: New method and reference range. Range previously listed as <116 IU/mL.



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