Immunoglobulin A, Qn, Serum

Laboratory assay overview

Cerebellar ataxia may occur as a result of autoantibodies to cerebellar targets. These may include antibodies to the Purkinje cell antigen Yo, the voltage gated calcium channel (VGCC) or tissue transglutaminase (tTG). Glutin ataxia is associated with widespread tissue transglutaminase (tTG) IgA deposition around vessels in the cerebellum, pons, and medulla.

Laboratory assay overview

This test is used to aid in the diagnosis of gluten-sensitive enteropathies.

Laboratory assay overview

This test is used to aid in the diagnosis of gluten-sensitive enteropathies.

Laboratory assay overview

This test is used to aid in the diagnosis of gluten-sensitive enteropathies

Laboratory assay overview

This test is used to aid in the diagnosis of gluten-sensitive enteropathies.

Laboratory assay overview

This test is used to aid in the diagnosis of gluten-sensitive enteropathies.

Laboratory assay overview

Celiac disease is caused by an immune response to gluten in genetically sensitive individuals. The diagnosis is largely based on a biopsy of the small intestine, but serologic tests also help support a diagnosis and may assist identification of patients who may require biopsy. Tissue transglutaminase antibodies (tTG, IgA) is a marker with 95% sensitivity and specificity. Total IgA is measured because 2-3% of celiac disease patients are IgA deficient. Because tTG, IgA, and anti-Gliadin IgA tend to decrease in patients on a gluten-free diet, these markers are also used to assess dietary compliance. The endomysial antibody (EMA, IgA) assay has high specificity for celiac disease and is used to confirm positive anti-tTG results.

Laboratory assay overview

This panel is used to assist in the diagnosis of celiac disease (CD). Background: CD is caused by an immune response to gluten in genetically sensitive individuals. Diagnosis begins with serologic testing and is confirmed by biopsy. This panel tests all specimens for tissue transglutaminase (tTG) IgA, which has 95% sensitivity and specificity for CD. Specimens positive for tTG IgA are tested for endomysial antibody (IgA), which may increase specificity for CD. This panel also tests all specimens for total IgA. A total IgA level below the reference range is suggestive of IgA deficiency and reflexes to IgG-based tests: tTG IgG and gliadin (deamidated) antibody (IgG); these tests are generally less sensitive than tTG IgA for CD but are useful in the context of IgA deficiency.

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

This panel assists in differentiating celiac disease from other inflammatory bowel diseases and helps avoid progression of celiac disease, particularly in children, through early identification of gluten sensitivity.

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

These studies contribute to the diagnosis of autoimmune blistering diseases, dermatitis herpetiformis, and IgA vasculitis. Important in the evaluation of other autoimmune and inflammatory skin diseases including non-IgA vasculitides and interface and lichenoid dermatitis/mucositis such as connective tissue disorders, lichen planus, etc. The panel includes the C5b-9 antibody to better distinguish between some forms of Lupus and Dermatomyocitis. Its presence or absence is also critical in the evaluation of other types of connective tissue diseases and many vasculitides.

Laboratory assay overview

Increased IgA is associated with monoclonal IgA myeloma, respiratory and gastrointestinal infections, and malabsorption; decreased IgA is found in selective IgA deficiency and in ataxia telangiectasia.

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

IgA, the predominant immunoglobulin secreted at mucosal surfaces, consists of 2 subclasses. IgA1 is the major subclass and accounts for 80% of total IgA in serum, whereas IgA2 is the major subclass in secretions such as milk. Low concentrations of IgA2 with normal IgA1 levels suggest an IgA2 deficiency. Antigenic sites on the IgA subclasses are responsible for the anaphylactic transfusion reactions experienced by some patients totally deficient in either IgA1 or IgA2. After repeated transfusions, such patients may produce antibodies to these antigens. Thus, IgA subclasses are useful in evaluating patients with anaphylactic transfusion reactions. Elevated concentrations of IgA2 with normal or low amounts of IgA1 suggest a clonal plasma cell proliferative disorder secreting a monoclonal IgA2. Grossly elevated levels of either subclass can occur in patients with IgA myeloma. IgA subclasses are of further importance in certain pathogenic microorganisms, including Haemophilus influenzae, which are capable of enzymic cleavage of IgA1, leading to partial inactivation of this subclass. Recurrent sinopulmonary infections may, therefore, be related to deficiency of IgA2, which is resistant to these organisms.

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

Measurement of immunoglobulin A aids in the diagnosis of abnormal protein metabolism and the body's lack of ability to resist infectious agents.

Laboratory assay overview

Detect and identify monoclonal immunoglobulin gammopathies

Laboratory assay overview

Detect and identify monoclonal immunoglobulin gammopathies

Laboratory assay overview

This test is used to detect and identify monoclonal gammopathy (M protein) found on serum protein electrophoresis; diagnose myeloma, macroglobulinemia of Waldenström; evaluate amyloidosis; evaluate lymphoproliferative disease (malignant lymphoma and others) and collagen disease in general; and diagnose and characterize immune deficient and dysgammaglobulinemic states.

Laboratory assay overview

This test is used to detect and identify monoclonal immunoglobulin gammopathies in the presence of therapeutic monoclonal antibody (mAbs) drug treatment with Daratumumab (Dara®), a human IgG1 κ mAb, which migrates in the electrophoretic γ globulin zone of the electrophoresis gel. In this laboratory procedure, the Dara® in vitro interference is removed using an anti-daratumumab antibody reagent. This procedure will characterize the specific light and heavy chain components of a monoclonal protein without Dara® interference.

Laboratory assay overview

Detect and identify monoclonal immunoglobulin gammopathies in the presence of therapeutic monoclonal antibody (mAbs) drug treatment with isatuximab (SARCLISA®), a human IgG1 kappa mAb, which migrates in the electrophoretic gamma globulin zone of the electrophoresis gel. In this laboratory procedure, the isatuximab in vitro interference is removed using an anti-isatuximab antibody reagent. This procedure will characterize the specific light and heavy chain components of a monoclonal protein without isatuximab interference.

Laboratory assay overview

Evaluate humoral immunity; monitor therapy in IgA myeloma

Laboratory assay overview

Study IgA deficiencies in patients in association with recurrent sinopulmonary infections or repeated transfusions; study IgA elevations associated with IgA myeloma

Laboratory assay overview

Elevations of IgG, A and/or M are seen in generalized hypergammaglobulinemia, chronic inflammatory conditions and in lymphoproliferative diseases such as multiple myeloma, lymphoma and leukemias. Decreased levels are found in immunodeficiency states, generalized hypogammaglobulinemia and in unrecognized pediatric patients.