POCT
What does POCT stand for?
Point-of-Care Testing
What is active agglutination?
antigen inherent to (naturally on) particle such as RBC
What is a label?
molecule attached to antigen or antibody in an immunoassay that allows for detection of
antigen-antibody complex formation
The principle Nephelometry and Turbidimetry
immunoprecipitation
Define PCR
Polymerase Chain Reaction
Name an example of a POCT?
Glucose, Hgb, Pregnancy Test, Rapid Strep, Flu
What is passive agglutination?
Inert particles coated with soluble antigen react with antibody in serum
In chemiluminescent immunoassays, the product detected is?
Photons of Light
What does Turbidimetry measure? What does Nephelometry measure?
Turbidimetry-transmitted light
Nephelometry- scattered light
What are the 3 cycles of PCR?
Denaturing
Annealing
Elongation
What are the 3 categories of testing according to CLIA?
Waived, Moderately Complex, High Complex
What is reverse passive agglutination?
Antibody is absorbed onto inert particles and reacts with antigen in serum
What is the difference in homogenous assays and heterogenous assays?
heterogenous requires a separation step/washing step
What is the principle of Flow Cytometry?
fluorescent-labeled monoclonal antibody binds to specific CD marker (antigen) on cells, pass thru flow cell where they are exposed to laser beam, labeled cells fluoresce
What is FISH? not the animal ;)
Describe the process.
fluorescent
in situ hybridization
labeled probes are hybridized with tissues, cells, or chromosomes that have
been fixed onto a glass slide following incubation with the probe, unbound probes are removed by
washing
the slides are viewed under a fluorescent microscope
Name some advantages and disadvantages of POCT?
Advantages:
Fast
Easy
Less complicated/ painful specimen collection
Still just as accurate as testing within the lab
Disadvantages:
Expensive!
Need proper training to perform tests properly
What is Precipitation?
soluble antigen combines with soluble antibody forming insoluble immune complexes
Which immunoassay measures IgE in response to specific allergen?
RAST
Name a clinical application Flow Cytometry is used for in the lab.
Monitor progression of leukemias and HIV/AIDS
What are some advantages and disadvantages of PCR?
Advantages: Increased sensitivity and specificity, Faster diagnosis than waiting for culture and
sensitivity, no interferences or cross reactivity like in serology tests
Disadvantages: Cost, Must know target DNA sequence, Still susceptible to lab errors such as
contamination
What is the greatest source of error in POCT?
Pre-Analytical (patient identification, improper collection)
Which Ig class is best in agglutination and which is best in precipitation?
Agglutination-IgM
Precipitation-IgG
The hCG test is an example of which immunoassay method?
immunochromatography
What is the normal CD4:CD8 ratio?
What is the ratio in HIV/AIDS patients?
Normal 2:1
HIV/AIDS: 0.5:1
What is DNA sequencing?
Determining the order of nucleotides in a DNA molecule