Testing: Labeling Flashcards
Anti-dsDNA in ELISA
Associated with drug induced systemic lupus erythematosus mixed connective tissue disease, rheumatoid arthritis, scleroderma and Sjögren’s syndrome
Speckled
Uniform points of fluorescence scattered throughout nucleus with NO nucleolar staining, c’somes are weak or do not stain
Antigens include: Sm, RNP, Scl-70, SS-A, SS-B
Nucleolar
Fluorescent nucleoli (often occurring with speckled), c’somes faint or non-staining
Anti-centromere
Discreetly speckled on non-mitotic cells and chromosome associated speckling on the mitotic cells.
On cells in metaphase the ACA will appear as striations perpendicular to the long axis of the chromosome region, the pattern is suggestive of the CREST.
Spindle
Only the spindle fluorescences in cells undergoing mitosis, the spindles consist of a network of threads connecting the centers ones to each other, suggesting antibodies to microtubules.
Cytoplasmic
Suggestive of mitochondrial antibodies, smooth muscle antibodies, or other auto antibodies
Anti-Mitochondrial Antibodies
Cytoplasmic speckles in a fibrous network mainly in the cytoplasm of resting and mitotic cells
Anti-smooth muscle antibodies
Fine fibrous staining of the entire cytoplasm of cells with a “spiderweb” appearance, the staining is uniform over the entire cytoplasm and extends over the nucleus
Diffuse (Homogeneous)
Entire nucleus is fluorescent due to antibody to nuclei protein or histones, mitosis cells stain as “intensely stained irregularly shaped mass”. High titers can be suggestive of SLE
ANA testing
Determined via indirect immunofluorescence, for diagnostic or prognostic use in progressive systemic sclerosis, mixed connective tissue disease, Sjögren’s syndrome, polymyositis and rheumatoid arthritis
Titer Interpretation Of DNase test
Indicator in substrate is TOLUIDINE BLUE, which changes from blue to pink color
Toluidine Blue + DNA (which has been depolymerized by enzyme) = PINK
If patient has Ab to DNase-B, neutralization of the enzyme will inhibit the depolymerization of DNA Toluidine Blue + DNA = BLUE
Enzyme Immunoassay
An immunoassay that employs an enzyme label on one of the reactants
Fluorescent Immunoassay
Uses a fluorescent compound which absorbs light or energy (excitation energy) at a specific wavelength and then emits light or energy at a different wavelength
Fluorescence polarization immunoassay (FPIA)
An immunoassay based on the change in polarization of fluorescent light emitted from a labeled molecule when it is bound by antibody
Chemiluminescent Immunoassay
An immunoassay technique in which the antigen or antibody is labeled with a molecule capable of emitting light during a chemical reaction; this light is used to measure the formation of the antigen-antibody complex
Nucleic acid probe
Short strand of DNA or RNA of a known sequence used to identify a complementary nucleic acid strand in a patient specimen
Dot-blot
A serological test that uses microparticles of antigen using an antibody that has a fluorescent tag attached
Sandwich hybridization
A nucleic acid detection method using two probes, one of which is placed on a solid support, such as a membrane or microtiter plate, to capture the target DNA. A second labeled probe, which binds to a second site on the target DNA, is added to detect specific gene sequences
Southern blot
Technique for the identification of specific DNA sequences in which DNA is cleaved into fragments by enzymes, separated electrophoretically, denatured, transferred to a nitrocellulose membrane, and incubated with a labeled probe that is specific for the sequence of interest
Northern blot
Technique for the identification of specific RNA sequences by separating short RNA molecules electrophoretically, denaturing them, transferring the pattern to a nitrocellulose membrane, and incubating with a labeled probe that is specific for the sequence of interest
Radioimmunoassay (RIA)
A technique used to measure small concentrations of an analyte, using a radioactive label on one of the immunologic reactants
Immunoradiometric Assay (IRMA)
The antibodies are labeled with radioisotopes which are used to bind antigens present in the specimen. When a positive sample is added to the tubes, radioactively labeled antibodies bind to the free epitopes of antigens and form an antigen-antibody complex. Unbound labeled antibodies are removed by a second reaction with a solid phase antigen. The amount of radioactive remaining in the solution is direct function of the antigen concentration
Competitive immunoassay
An immunoassay in which unlabeled and labeled antigen compete for a limited number of binding
sites on reagent antibody.
Noncompetitive assay
An assay in which an excess of binding sites is present so that all the patient analyte can be bound and measured.
Homogeneous enzyme immunoassay
An immunoassay in which no separation step is necessary. It is based on the principle of a decrease in enzyme activity when specific antigen–antibody combination occurs.
Heterogeneous enzyme immunoassay
Immunoassay in which enzyme is used as a label and which requires a separation step to separate free from bound analyte.
FTA-ABS
Used for Treponemal testing in Syphilis
Pt Ab binds to T. pallidum Ag and a conugate binds the Ab
EMIT
Enzyme Multiplied Immunoassay Technique
Uses Ab and an enzyme that is attached to the analyte being tested for. Ab that does not become bound to the target instead bind this analyte-bound enzyme. The enzyme is deactivated when antibodies bind to its analyte portion.
High amount of target is present, it will bind most of the Ab, leaving enzymes free in solution. High amoutns of substrate will be converted by the high concentration of free enzyme.
Low concentration of target is present, binding few Ab, leaving a high amount of Ab to bind the enzymes and deactivate them. Little substrate will be converted.
