Thyroid Peroxidase Ab

Laboratory assay overview

The antinuclear antibodies test detects autoantibodies that bind to the nuclear components of HEp-2 cells. A positive antinuclear antibodies titer is not specific but indicates the presence of one or more autoantibodies. Profiles of specific autoantibodies have diagnostic and potential prognostic utility for several autoimmune diseases. This profile helps differentiate between eight autoimmune disease states: SLE • Antinuclear antibodies by IFA Tests with high specificity • Anti‐dsDNA by Farr • Anti‐SM Tests with moderate specificity • Anti‐Ro • Anti‐La • Anti‐Chromatin • C3 & C4 Complements • Anticardiolipin IgG, IgA & IgM Drug‐induced SLE • Anti‐Chromatin Sjogren’s Syndrome • Anti‐Ro • Anti‐La Rheumatoid Arthritis • Anti‐CCP (high specificity) • Rheumatoid Factor (Turbidimetry) Mixed Connective Tissue Disease (MCTD) • Anti-U1 RNP Limited Scleroderma (CREST) • Anti-Centomere Diffuse Scleroderma • Anti-SCL-70 by EIA, confirmed by a second method Autoimmune Thyroid Disease • Anti-Thyroid Microsomal (TPO)

Laboratory assay overview

The antinuclear antibodies test detects autoantibodies that bind to the nuclear components of HEp-2 cells. A positive antinuclear antibodies titer is not specific but indicates the presence of one or more autoantibodies. Profiles of specific autoantibodies have diagnostic and potential prognostic utility for several autoimmune diseases. This profile helps differentiate between eight autoimmune disease states: SLE • Antinuclear antibodies by IFA Tests with high specificity • Anti-dsDNA by Farr • Anti-SM Tests with moderate specificity • Anti-Ro • Anti-La • C3 & C4 Complements • Anticardiolipin IgG, IgA & IgM Sjogren’s Syndrome • Anti-Ro • Anti-La Mixed Connective Tissue Disease (MCTD) • Anti-U1 RNP Limited Scleroderma (CREST) • Anti-Centromere Diffuse Scleroderma • Anti-SCL-70 by EIA, confirmed by a second method Autoimmune Thyroid Disease

Laboratory assay overview

This panel can be helpful in the diagnosis of Sjogren syndrome by simultaneously testing for antinuclear antibodies (ANAs) with an immunofluorescence assay (IFA), performed on human epithelial type 2 (HEp-2) cells, as well as SSA antibodies, SSB antibodies, rheumatoid factor (RF), thyroid peroxidase (TPO) antibodies, and anti-mitochondrial antibodies (AMAs). For specimens with positive ANA IFA results, reflex testing for ANA titer and pattern is performed. For specimens with positive AMA results, reflex testing for AMA titer is performed. The laboratory evaluation for individuals with clinical suspicion of autoimmune diseases often begins with an ANA screen. The classic ANA IFA on HEp-2 cells is considered by the American College of Rheumatology (ACR) as the current gold standard because of its overall high sensitivity for several autoimmune diseases [1]. Knowing the ANA titer and fluorescent staining pattern can be helpful in interpreting positive results [2]. Individuals with negative results on the ANA IFA usually also have negative results on specific autoantibodies. However, SSA antibody may be detected in some ANA IFA-negative patients with lupus or Sjogren syndrome [3]. The 2012 ACR classification criteria for Sjogren syndrome indicate that testing for SSA or SSB antibody has the highest sensitivity and specificity, and that a positive RF result in addition to an ANA titer ≥1:320 is consistent with Sjogren syndrome [4]. However, the 2016 ACR/European League Against Rheumatism (EULAR) classification criteria for Sjogren syndrome do not include SSB/La, RF, and ANA titer, because studies showed that these markers do not add sufficient value to SSA/Ro testing [5]. Primary Sjogren syndrome is associated with an increased frequency of certain other autoimmune diseases [6]. Detecting characteristic markers, such as AMAs for primary biliary cholangitis and TPO antibodies for autoimmune thyroid disease, may aid in the evaluation of coexisting autoimmune diseases. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings. References 1. Methodology of testing for antinuclear antibodies (position statement). 2009. American College of Rheumatology. Updated December 2019. Accessed May 15, 2023. https://assets.contentstack.io/v3/assets/bltee37abb6b278ab2c/blta48818378bc89445/acr-position-statement-methodology-testing-antinuclear-antibodies.pdf 2. Tozzoli R, et al. Am J Clin Pathol. 2002;117(2):316-324. 3. Yazdany J, et al. Arthritis Care Res (Hoboken). 2013;65(3):329-339. 4. Shiboski SC, Arthritis Care Res (Hoboken). 2012;64(4):475-487. 5. Shiboski CH, et al. Ann Rheum Dis. 2017;76(1):9-16. 6. St. Clair EW, et al. Sjogren's Syndrome. In: Firestein GS, et al, eds. Kelley & Firestein's Textbook of Rheumatology. 10th ed. Elsevier; 2017.

Laboratory assay overview

This panel can be helpful in the diagnosis of systemic rheumatic disorders and other autoimmune diseases. Although the test for antinuclear antibodies (ANA) is strongly associated with systemic lupus erythematosus (SLE), the laboratory evaluation for individuals with clinical suspicion of a variety of autoimmune diseases often begins with an ANA screen. This panel simultaneously tests for ANA (using immunofluorescence) as well as the important specific autoantibodies associated with a positive ANA. It also includes testing for complement proteins, rheumatoid arthritis, Sjogren's syndrome, systemic sclerosis, polymyositis, anti-phospholipid antibody syndrome, and autoimmune thyroid disease.

Laboratory assay overview

In virtually all cases of Hashimoto’s disease and in the majority of Graves’ disease cases, Anti-TPO autoantibodies are elevated. High levels of Anti-TPO autoantibodies, in the context of the clinical presentation of hypothyroidism, confirms the diagnosis of Hashimoto’s disease.

Laboratory assay overview

This test is used for diagnostic evaluation of patients with possible chronic urticaria.

Laboratory assay overview

Chronic urticaria is a common skin disorder affecting 1% to 6% of the general population. It is characterized by repeated occurrence of short-lived cutaneous wheals accompanied by redness and itching. Autoimmune urticaria is defined by the presence of a functional IgG antibody to high-affinity IgE receptor (Fc epsilon RI alpha) or to IgE. These antibodies trigger mast cell and basophile degranulation by the engagement of Fc epsilon receptor. Functional IgG antibody to the receptor has been identified in approximately 30-40% of patients with chronic urticaria, and anti IgE antibody has been identified in another 5-10%.

Laboratory assay overview

Patients with a chronic form of urticaria who are positive with the functional Histamine Release (Chronic Urticaria) test have an autoimmune basis for their disease. A positive result does not indicate which autoantibody (anti-IgE or anti-Fc epsilon RI alpha chain) is present. A positive anti-IgE antibody does not exclude the presence of anti-Fc epsilon RI alpha chain antibody. Autoimmune thyroid disease coexists in approximately 25% of autoimmune chronic urticaria patients.

Laboratory assay overview

This panel can be helpful in the diagnosis of systemic lupus erythematosus (SLE) and several other autoimmune diseases, including mixed connective tissue disease, Sjogren syndrome, systemic sclerosis, and autoimmune thyroid disease. The panel simultaneously tests for antinuclear antibodies (ANAs) with an immunofluorescence assay (IFA), performed on human epithelial type 2 (HEp-2) cells, and 11 biomarkers associated with these conditions. For specimens with positive ANA IFA results, reflex testing for ANA titer and pattern is performed. The ANA testing has high sensitivity (97%) for SLE but limited specificity (34%) [1]. Thus, a positive ANA test does not exclude other autoimmune diseases with similar clinical features [2]. Testing for specific antibodies in a panel may expedite the evaluation of SLE but is generally not recommended [3]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings. References 1. Petri M, et al. Arthritis Rheum. 2012;64(8):2677-2686. 2. Kavanaugh A, et al. Arch Pathol Lab Med. 2000;124(1):71-81. 3. Yazdany J, et al. Arthritis Care Res (Hoboken). 2013;65(3):329-339.

Laboratory assay overview

This panel may be helpful in the diagnostic evaluation of individuals with suspected primary biliary cholangitis (PBC). This panel includes anti-mitochondrial antibody (AMA), with reflex to titer; an antinuclear antibody (ANA) immunofluorescence assay (IFA) screen, performed on human epithelial type 2 (HEp-2) cells, with reflex to titer and pattern; actin (smooth muscle) antibody (SMA; IgG); Sjogren antibodies (SSA, SSB); thyroid peroxidase (TPO) antibody; and liver kidney microsome type 1 (LKM-1) antibody (IgG). PBC can be diagnosed by fulfilling 2 of the 3 diagnostic criteria that comprise biochemical evidence, histologic evidence, and the presence of PBC-specific antibodies [1]. Presence of AMAs is the serologic hallmark of PBC and can be detected in approximately 95% of patients. ANAs are detected in 10% to 30% of patients with PBC. The presence of certain ANAs patterns including those associated with antibodies to sp100 or gp210 have diagnostic value, especially in AMA-negative PBC [1, 2]. Other antibodies included in this panel may aid in differential diagnosis or identify concomitant autoimmune diseases. Antibodies to SSA and SSB are associated with Sjogren syndrome, an autoimmune disease frequently diagnosed in patients with PBC [1]. SMAs are present in most patients with type 1 autoimmune hepatitis (AIH) but can be detected in a range of other conditions, such as viral hepatitis, malignancies, rheumatic diseases, and nonalcoholic fatty liver disease. LKM-1 antibody is characteristic for type 2 AIH in the absence of hepatitis C. TPO antibodies are associated with autoimmune thyroid disease, which is common in patients with PBC [2]. Note that the presence of these antibodies does not confirm the coexistence of associated autoimmune diseases [1]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings. References 1. Lindor KD, et al. Hepatology. 2019;69(1):394-419. 2. Neuberger J, et al, eds. Autoimmune Liver Disease: Management and Clinical Practice. 1st ed. John Wiley & Sons Ltd, 2020

Laboratory assay overview

Differential diagnosis of hypothyroidism and thyroiditis

Laboratory assay overview

This test is used for differential diagnosis of hypothyroidism and thyroiditis.

Labcorp population reference ranges

Labcorp calculates these statistical intervals for this specific assay and demographic group, not as universal optimal targets.

Quest Diagnostics population reference ranges

Quest Diagnostics calculates these statistical intervals for this specific assay and demographic group, not as universal optimal targets.

Laboratory assay overview

Assists in the diagnosis of thyroid diseases such as endemic goiter, Graves Disease, autoimmune thyroiditis, Addison's Disease, insulin-dependent diabetes mellitus, Hashimoto's Disease and polyendocrine auto-immunopathies.

Laboratory assay overview

Assists in the diagnosis of thyroid diseases such as endemic goiter, Grave's Disease, autoimmune thyroiditis, Addison's Disease, insulin-dependent diabetes mellitus, Hashimoto'sDdisease and polyendocrine auto-immunopathies. Also valuable as a part of the thyroid autoimmune diagnostic profile.