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whats the procedure for western blot
- pt serum is added to nylon test strip
- strip is incubated and any HIV antibodies will bind to antigens on the membrane
- unbound antibodies are washed
- antiantibodies with enzyme label (conjugate) are added and binds to anti antibodies
- unbound conjugate is washed leaving bound conjugate (labeled enzyme)
- colored bands appear in positions of HIV antibodies present
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western blot tests for
HIV antibodies
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what are the negative, positive, indeterminate, results look like on a western blot
- negative control: no band or band correspondence
- positive control: matching bands
- indeterminate: some matched bands but not enough for a positive result
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what are some indeterminate results caused by in the western blot
- contaminants
- false positives
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HCG tests for
B subunit of human chorionic gonadotropin, a glyoprotein produced in the placenta shortly after fertilization
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false negatives of HCG
- very diluted specimen
- interference by HAMA (human antimouse antibodies)
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false positives of HCG
- tumors producing elevated HCG
- trophoblastic disease
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purpose of cold agglutination titers
- to test for titers for agglutination at temps below 37 C
- reaction of strength is greatest at 0-4 C
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what are the two groups of cold agglutinations
- 1. harmless, present in all normal sera
- 2. pathogenic found in chronic hemagglutanin and infection
- malaria, mono, influenza, cirrhosis
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what type of diease does cold agglutination titers used for
mycoplasma pneumoniae
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what does RF hemagglutanin test for
- rheumatoid factor (RF): an antibody produced in rheumatoid arthritis (joint inflammation)
- RF proteins are class IgM that act as antibodies, binding to Fc of IgG
- uses sheep agglutinins as carriers , rabbit gamma globulin
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false positives of RF hemagluttanin
mono
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RPR tests for
- non treponemal tests for damaged cells, detecting antibodies against cardiolipin (reagin)
- RPR stands for "rapid plasma reagin" which are IgM or IgG class
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RPR is based on
flocculation: precipitation occurring over narrow range of antigen concentration using charcoal antigens as carriers
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treponemal tests for
- specifically treponema pallidium in syphilis, used to positively confirm true positive from false positives in nontreponemal tests
- FTA (flouresecent treponemal antibody)
- TRPA (treponemal pallidium particle agglutination)
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describe the antibody concentration of treponemal and nontreponemal test (treated + untreated)
- treponemal antibodies will be 100% reactive in secondary and latent syphilis
- non treponemal when untreated will decrease during latent stage but will remain in the body
- treponemal when treated will decrease completely from latent stage and further
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(TP-PA) T pallidium particle agglutination test
- a type of particle agglutination test using sheep RBCs to test for T palliudium
- treponemal test
- sensitive for primary syphilis
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describe FTA-ABS
- flourescent treponemal antibody absorption test
- a dilution of heat inactivated patient serum with treponemes is added to a well and washed to removed excess conjugate. The antibody conjugate will flourescense
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describe tests for infectious mononuceleosis
- caused by Epstein Bar Virus (EBV)
- using heterophile horse agglutinins, IgM class
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what could result in false positives for mono
- hepatitis
- leukemia
- rubella
- rheumatoid arthritis
- burketts lymphoma
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describe spread of contact, anEpstein Barr Virus
- spread through salivary excretions
- symptoms are fever lymphadenopathy, sore throat, fatigue
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whats found on the blood smear for infectious mono
- reactive lymphs, high lypmh count of 50%
- presence of heterophile IgM antibodies to certain EBV antigens
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what is the test to detect for heterophile antibodies of IM
- used to be monospot now test for immunochromatographic assay using bovine RBC antigen
- indirect immunoflourescence (IFA) assay using EBV infected cells: most sensitive and highest specificity
- ELISA using synthetic EBV proteins
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