Instrumentation Exam 3

Antibody

protein made by B cells that binds to specific antigens

Antigen

foreign substances that trigger an immune response

Affinity

strength of bond between one antigen and one antibody site

Avidity

total strength of all bonds between antigen and antibody

primary reaction

First binding between antigen and antibody (immunofluorescence) = (ELISA, RIA, EMIT, FPIA)

Secondary

visible reaction (agglutination, precipitation)

Tertiary

body’s response to primary + secondary (complement activation, phagocytosis)

Quaternary

complex reactions (advanced immunoassays, molecular tests)

primary ex.

drug testing

secondary ex.

pregnancy test, latex, immunoelectrophoresis, blood typing

tertiary ex.

allergy + skin test (TB)

Quaternary ex

DNA, PCR, Chemoilluminescent, Flow cytometry

4+: strong; all cells agglutinated

3+: strong; few free cells

2+: moderate; some free cells

1+: weak; mostly free cells

0: no agglutination

Preventative Maintenance

improve product quality, lower repair costs, greater operator safety

automated clot detection

turbidimetric, nephelometric, mechanical, viscosity-based

turbidimetric

a light source used to measure opacity; less light passes as the clot forms

nephelometric

detectors used to measure light scatter due to fibrinogen forming 

mechanical

the electrical circuit opened/closed when the ball moved away from the magnet because of fibrinogen forming on the ball

viscosity-based

steel ball amplitude measured, moved with magnetic field

normal: balanced clotting

hyperfibrinolysis: clot breaks down too fast

thrombocytopenia: low platelet count, leading to weak clot formation

hypercoagulation: excessive clotting

Platelet aggregation reagents

ADP, Collagen, Epinephrine, Ristocetin, Arachidonic acid

ELISA enzyme labels

horseradish peroxide (HRP), alkaling phosphatase (ALP), beta-galactosidase

PCR steps summarized

denaturation- DNA strands separate

annealing- primers bind

extension- polymerase copies DNA

Long summary of PCR

enzymatically synthesizes millions of identical copies of target DNA to increase analytic sensitivity 

when the target is microbial RNA or mRNA, RNA must be enzymatically converted to DNA by reverse transcriptase (RT)

latest innovation: real time RT-PCR

DNA melt curve analysis

PCR: limited by expense, need for special thermocyclers, potential aerosol contamination, nonspecific annealing & degree of stringency

Coagulation screening tests

PT, aPTT, TT, Fibrinogen, D-dimer

Bleeding time

manual method that evaluates primary hemostasis (being replaced by PFAs)

• checks how long it takes for bleeding to stop after a small cut

• tells you if platelets are working properly

Prothrombin time (PT)

extrinsic and common pathways

• checks how long it takes blood to clot through the extrinsic and common pathways

• used to monitor people taking warfarin (a blood thinner)

• if PT is longer than normal, blood takes too long to clot

Activated Partial thromboplastin time (aPTT)

intrinsic and common pathways

• checks the intrinsic and common pathways

• used to monitor heparin therapy (another blood thinner)

• if aPTT is long, problem in the intrinsic pathway or heparin effect

Thrombin Time (TT or TCT)

conversion of fibrinogen to fibrin

• measures how well fibrinogen turns into fibrin, which makes the final clot

• if TT is long, it means: there is a fibrinogen problem, or heparin is still in the sample

quantitative fibrinogen

determines the amount of fibrinogen 

• if it is low, the body can’t form a strong clot, more risk

D-dimer

detects fragments from the plasmin degradation of the fibrin clot

• checks for clot breakdown products (tiny pieces left when a clot dissolves)

• if high, it means the body has recently made and broken down clots

Nucleic probe testing infectious

salmonella, COVID-19, HIV, Hepatitis, Chlamydia, Gonorrhea, TB, Herpes

nucleic probe testing genetic

cystic fibrosis, sickle cell, huntington’s, Von Willebrand’s disease, Duchenne type, muscular dystrophy

left side: 2 heavy + 2 Light chains, Fab (binds antigen), Fc (binds immune cells), Hinge (flexibility)

prozone

(antibody excess) too many antibodies= false negative

postzone

(antigen excess) too many antigens= false negative

zone of equivalence

(create insoluble complex) balanced= positive reaction

ELISA

enzyme linked immunosorbent assay

EMIT

enzyme multiplied immunoassay technique

RIA

radioimmunoassay

FPIA

fluorescence polarization immunoassay