Testing: Labeling

Question 1

Anti-dsDNA in ELISA

Answer 1

Associated with drug induced systemic lupus erythematosus mixed connective tissue disease, rheumatoid arthritis, scleroderma and Sjögren’s syndrome

Question 2

Speckled

Answer 2

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

Question 3

Nucleolar

Answer 3

Fluorescent nucleoli (often occurring with speckled), c’somes faint or non-staining

Question 4

Anti-centromere

Answer 4

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.

Question 5

Spindle

Answer 5

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.

Question 6

Cytoplasmic

Answer 6

Suggestive of mitochondrial antibodies, smooth muscle antibodies, or other auto antibodies

Question 7

Anti-Mitochondrial Antibodies

Answer 7

Cytoplasmic speckles in a fibrous network mainly in the cytoplasm of resting and mitotic cells

Question 8

Anti-smooth muscle antibodies

Answer 8

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

Question 9

Diffuse (Homogeneous)

Answer 9

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

Question 10

ANA testing

Answer 10

Determined via indirect immunofluorescence, for diagnostic or prognostic use in progressive systemic sclerosis, mixed connective tissue disease, Sjögren’s syndrome, polymyositis and rheumatoid arthritis

Question 11

Titer Interpretation Of DNase test

Answer 11

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

Question 12

Enzyme Immunoassay

Answer 12

An immunoassay that employs an enzyme label on one of the reactants

Question 13

Fluorescent Immunoassay

Answer 13

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

Question 14

Fluorescence polarization immunoassay (FPIA)

Answer 14

An immunoassay based on the change in polarization of fluorescent light emitted from a labeled molecule when it is bound by antibody

Question 15

Chemiluminescent Immunoassay

Answer 15

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

Question 16

Nucleic acid probe

Answer 16

Short strand of DNA or RNA of a known sequence used to identify a complementary nucleic acid strand in a patient specimen

Question 17

Dot-blot

Answer 17

A serological test that uses microparticles of antigen using an antibody that has a fluorescent tag attached

Question 18

Sandwich hybridization

Answer 18

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

Question 19

Southern blot

Answer 19

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

Question 20

Northern blot

Answer 20

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

Question 21

Radioimmunoassay (RIA)

Answer 21

A technique used to measure small concentrations of an analyte, using a radioactive label on one of the immunologic reactants

Question 22

Immunoradiometric Assay (IRMA)

Answer 22

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

Question 23

Competitive immunoassay

Answer 23

An immunoassay in which unlabeled and labeled antigen compete for a limited number of binding
sites on reagent antibody.

Question 24

Noncompetitive assay

Answer 24

An assay in which an excess of binding sites is present so that all the patient analyte can be bound and measured.

Question 25

Homogeneous enzyme immunoassay

Answer 25

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.

Question 26

Heterogeneous enzyme immunoassay

Answer 26

Immunoassay in which enzyme is used as a label and which requires a separation step to separate free from bound analyte.

Question 27

FTA-ABS

Answer 27

Used for Treponemal testing in Syphilis

Pt Ab binds to T. pallidum Ag and a conugate binds the Ab

Question 28

EMIT

Answer 28

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.