![]() ![]() ![]() Positive in acute active stage with viral replication (infectivity factor) highly infective Positive in acute stage of hepatitis B earliest indicator of acute antigen infection also indicates chronic infection Indicates previous exposure and immunity to hepatitis A Positive for acute stage of hepatitis A, develops early in disease course TABLE 8.8 Markers That Appear After Infection No known cases originated in the United States international travelers are the only high-risk group to date Requires active infection with HBV injection drug users and persons receiving clotting factor concentrates are at highest risk for infection Total antibody to delta hepatitis shows if ever infected IgM test is in research laboratories ELISA Injection drug use, occupational exposure to blood, hemodialysis, transfusion, possibly sexual transmission Sexual promiscuity, male-to-maleto-female sexual practices, injection drug use, birth to an infected motherĮLISA is the initial test to show if ever infected it should be confirmed by another test such as PCR HBsAg the best test for acute or recent infection is IgM antibody to HBcAg Household or sexual contact with an infected person, day care centers, and common source outbreaks from contaminated food IgM antibody to hepatitis A capsid proteins TABLE 8.6 Differential Diagnosis of Viral Hepatitisįecal-oral by person-toperson contact or ingestion of contaminated food Infectious disease such as tuberculosis, hepatitis C virus, and HIV Uses cDNA probes directed against ribosomal RNAĪmplifies nucleic acid to identify presence of bacterial or viral load Restriction fragment length polymorphism (RFLP)Įpidemiology of nosocomial and communityacquired infections Lymphocyte immunophenocytology differentiates B cells from T cells and T-helper cells from T-suppressor cells. Light scatter identifies cell size and granularity of lymphocytes, monocytes, and granulocytes color fluorochromes tagged to monoclonal antibodies bind to specific surface antigens for simultaneous detection of lymphocyte subsets. Quantitative immunoglobulins IgA, IgM, C-reactive protein, antistreptolysin O recorded in mg/dL or IU/mLīlood cell types are identified with monoclonal antibodies (mABs) specific for cell markers by means of a flow cytometer with an argon laser beam as the cells pass the beam, they scatter the light light energy is converted into electrical energy cells and stained with green (fluorescence) or orange (phytoerythrin). Light scatter proportionately increases as numbered size of immune complexes increases. Measures either antigen or antibody in solution through the scattering of a light beam antibody reagent used to detect antigen IgA, IgG, IgM concurrent controls are run to establish amount of background scatter in reagents and test samples. Slightest trace of infection can be detected more accurate than traditional tests for chlamydia genetic disorders Lyme disease, Epstein-Barr virus, extractable nuclear antibodies (connective tissue/systemic rheumatic disease)Įlectrophoresis separation of antigen subspeciesĭetection of antibodies of specific mobilityĪmplifies low levels of specific DNA sequences each cycle doubles the amount of specific DNA sequence.Įxponential accumulation of DNA fragment being amplified defects in DNA appear as mutations. Indirect EIA for quantification of an antigen or antibody enzyme and substrateĬolor change indicates enzyme substrate reaction. Hepatitis and human immunodeficiency virus (HIV) (screening)Įnzyme-linked immunosorbent assay (ELISA) Immunofluorescence (e.g., indirect fluorescent antibody )įluorescenttagged antibody reacts with antigen-antibody complex in the presence of ultraviolet light.Īntinuclear antibodies (ANAs) antimitochondrial antibodies (AMAs)Įnzymes are used to label induced antigen-antibody reactions.Ĭhromogenic fluorescent or luminescent change in substrate Soluble antigen reacts with corresponding antibody by ID or count.Ĭompetition between two antigen-antibody systems (test and indicator systems) Precipitation (e.g., immunodiffusion, counterimmunoelectrophoresis ) Treponemal, heterophile, and cold agglutinin antibodies Particulate antigen reacts with corresponding antibody antigen may be in form of RBCs (hemagglutination, latex, or charcoal coated with antigen). TABLE 8.1 Some Tests That Determine Antigen-Antibody ReactionsĪgglutination, hemagglutination (HA), immune hemagglutination assay (IHA) ![]()
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