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Antibody Testing. Sarah Ngov Ke Xin Li Seo Woo Tim Hong Jae Eun Shin Presentation Date: Sept 16, 2014. PHM142 Fall 2014 Instructor: Dr. Jeffrey Henderson. What is antibody testing?. Analyze patient’s sample to: determine absence/presence of a particular antibody
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Antibody Testing Sarah Ngov Ke Xin Li Seo Woo Tim Hong Jae Eun Shin Presentation Date: Sept 16, 2014 PHM142 Fall 2014 Instructor: Dr. Jeffrey Henderson
What is antibody testing? • Analyze patient’s sample to: • determine absence/presence of a particular antibody • determine the amount of antibody • Antibodies protect us against invading microscopic substances such as viruses, bacteria, chemicals & other toxins
What are antibodies? [3] • Each antibody is unique to an antigen • Antigen-antibody complexes signal immune system to fight off infection
IgA: present in body secretions; primary antibody in the mucous membranes of the gastrointestinal and respiratory tract and in saliva and tears IgD: present in small amounts & is thought to function in certain allergic responses IgE: present primarily in the skin and mucous membranes; believed to function in response to environmental antigens and allergic reactions IgG: widespread in the body; provides long-lasting defense against most bacterial invasions and other antigens IgM: large molecule found in blood and is involved in combating blood infections; first immunoglobulin produced following exposure to an antigen. [4]
Vaccines • designed to trigger an immune response and the production of antibodies prior to exposure to a potentially infectious microorganism • safe initial exposure → generate the blueprint for future protection • primary immune response creates IgM antibodies and a secondary response creates a supply of IgG antibodies
1. Detect Infection • Antibody level or presence in the blood indicate exposure to antigen or past infection • Evaluate protection level (immune status) • Viral Infections (e.g. HIV)
2. Diagnose Autoimmune Disorders • Measure the strength of an immune response to the body’s own tissue • E.g. Test for Antinuclear Antibodies (ANA)
Interpreting Test Results for allergen testing with IgG IgG testing: • ELISA/EIA (Enzyme-linked immunosorbent assay) • Commonly used to detect food allergies • Allergen-specific IgG antibodies measured • High levels of IgG subtypes serum concentrations may indicate food allergy. IgE testing: • Commonly used to test for environmental allergies →Look at level of IgE at serum level for diagnosis. →High levels of IgE subtypes serum concentrations may indicate environmental allergy.
Interpreting Test Results for auto-immune diseases Types of auto-antibody testing are developed for different types of autoimmune diseases: Acetylcholine receptor antibody: • Used to test for myasthenia gravis Anti-mitochondrial antibody: • used to detect biliary cirrhosis Anti-smooth muscle antibody (ASMA) • used to detect patients with active hepatitis
Interpreting Test Results for auto-immune diseases Anti-DNA antibody: • used to detect people with systemic lupus erythematosus Anti-nuclear antibody: • used to detect people with systemic lupus erythematosus as well as rheumatoid arthritis Anti-phospholipid antibody: • used to detect people with systemic lupus erythematosus as well as other autoimmune diseases.
HIV Antibody Test • Most common HIV test • Immunoassay of blood or urine or oral fluid sample that detects for HIV-1 and HIV-2 antibodies • Presence of these antibodies indicate positive result.
Interpreting Test Results for Hepatitis A • IgM anti-hepatitis A virus (HAV) antibodies • recent infection with hepatitis A • Total (IgM and IgG) antibodies to hepatitis A • previous or past infection, or immunity to hepatitis A
Interpreting Test Results for Hepatitis B • Hepatitis B surface antigen (HBsAg) • active hepatitis B infection, either recent or chronic • Antibody to hepatitis B core antigen (Anti-HBc) • recent or past hepatitis B infection • Antibody to HBsAg (Anti-HBs) • past hepatitis B infection • Or patient has received the hepatitis B vaccine • Hepatitis B type e antigen (HBeAg) • chronic hepatitis B infection and is actively contageous
Interpreting Test Results for Hepatitis C • Enzyme immunoassays (EIAs) • detect the presence of antibodies in serum directed against HCV • using HCV recombinant antigen derived from the nonstructural 4 gene, designated c100-3 • commonly used for initial detection of hepatitis C
Thyroid Antibody Testing • To diagnose an autoimmune thyroid disease
SUMMARY - Antibody testing serves as one of the tools that aid health care providers in diagnosis of immunodeficiencies. • Antibodies, or immunoglobulin proteins are part of the body’s immune system and help protect us against invading microscopic substances such as bacteria, viruses, chemicals and other toxins. They are made up of a four-chain basic structure consisting of two identical heavy chains and two identical light chains. Antigen-antibody complexes serve as signals for the rest of the immune system to destroy the infection. The body develops an antibody blueprint after exposure to the microorganism including IgM and IgG immunoglobulins. This is the basis for the mechanism of vaccines. - HIV Antibody test is an Immunoassay of blood or urine or oral fluid sample that detects for HIV-1 and HIV-2 antibodies. - Hepatitis A antibody testing is for IgM anti-HAV antibodies. Hepatitis C is diagnosed with HCV recombinant antigens. - Thyroid antibody test is used to diagnose an autoimmune thyroid disease (eg. Grave’s disease) - IgG testing are done to detect for food allergens. - Many different types of auto-antibodies are tested for (ex-acetylcholine receptor antibody) to detect for auto-immune diseases.
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