Disease States and Associated Laboratory Tests

42 Serial Dilution Relative Sensitivities of Calculations Serologic Methods Compare Pre & Post Titers Disease States and Associated...

42 Serial Dilution Relative Sensitivities of Calculations Serologic Methods Compare Pre & Post Titers Disease States and Associated to Determine Diagnosis of Measles and Rubella Laboratory Tests INFLAMMATION Definitions for Sensitivity 1. C-reactive protein (acu te ph ase and Specificity protein) a. Released rapidly after inflanunation or tissue damage 2. Specificity. b. Concentration quickly decreases as a. Analytical Specifici ty -Ability of inflammation subsides test to detect substance without c. Used to monitor presence of interference from cross-reacting inflammation &uh.stan ces d. Does not indicate source of b. Clinical Specificity - Ability of test inflammation to give negative result if patient e. High sensitivity CRP (hs-CRP) used does not have disease - high clinical to indicate risk of cor onary artery specificity test gives no false positives disea se 2. Erythrocyte sedimentation rate (ESR ) a. Also used to indicate presen ce of REMEMBER! inflamrna tion b. Not as sensitive to increasing or decreasing inflammation as CRP Test Sensitivities Nonlattice (More Sensitive) SYPHILIS lmmunoassays 1. Caused by Trepor1ema pallidum RIA (Radial Immunoassay) 0.001mg/ml EIA (Enzyme Immunoassay) 2. Course of disease : Primary, FIA (Fluorescent Immunoassay) secondary, latent, tertiary ; also Nepholometry congenital infections may occu r TREPONEMAL TESTS 1. Darkfield microscopy - used to Lattice (Less Sensitive) visualize motile organisms from CIE (Counter Current lmmunoelectrophoresis) primary & secondary lesions (..."tiori" or... "sion'J CF (Complement FixaliQ[]) 2. Fluorescent treponemal antibody Agglutination absorption test (FTA-Abs) a. Indirect immunofluorescence assay Flocculation (PrecipitaliQ[]) b. Remove nonspecific antibodies from Rocket Electrophoresis serum by using sorbent RID (Radial lmmunodiffusion) c. React serum with Nichol 's strain of Ouchterlony (Double immunodiffusion) T. pallidum !FE (lmmunofixalion) cl. Add fluorescein-labeled antihuman IEP (lmmunoelectrophoresis) globulin and wash e. Read for fluorescence 500 mg/ml  43 3. Treponema pallidum Immobilization Test (TPI) Sensitivity of Tests for Syphilis a. Darkfield microscopy b. Add live treponemes to patient PRIMARY STAGE serum c. If antibody is present, treponemes immobilized FrA-ABS } RPR VDRL i Sensitivity d. Expensive, seldom used 4. Microhemagglutination Assay for SECONDARY STAGE All Tests Equally Sensitive T. pallidum (MFIA-TP) a. Add patient serum to red cells sensitized with T. pallidum b. If antibody is present, agglutination LATE STAGE occurs FrA-ABS } Equal Sensitivity MHA-TP NONTREPONEMAL TESTS (REAGIN TESTS) TPI 1. Venereal Disease Research Laboratory Reagin Tests Negative in treated patients (VDRL) a. Microflocculation (microscopic) I FTA-ABS: Most Sensitive in All Stages I b. Antigen = cardiolipin + lecithin c. Antibody (reagin) = lgM or lgG RHEUMATOID ARTHRITIS (RA) directed against damaged tissue or organism 1. Production of IgM or IgG antibodies d. Serum requires heat inactivation directed against lgG e. Flocculation indicates reactive 2. Diagnosis requires radiologic, clinical serum and laboratory findings f. Test of choice for screening CSF g. False positive in malaria (100% 3. Laboratory findings biologic false positive), SLE, RA, a. High titer s of rheumatoid factor h epatitis, pneumonia, aging and (RF) infectious mononucleosis b. Low titers of complement c. Positive anti-cyclic citrullinated 2. Rapid Plasma Reagin Test (RPR) peptide (anti-CCP) a. Microflocculation and coagglutination of charcoal particles 4. Screening test: Rheumatoid factor (macroscopic) (RF) assay b. More sen sitive, less specific than a. Patient serum added to reagent VDRL composed of particulate carrier c. Antigen = cardiolipin + charcoal (latex or RBC) attached to lgG particles b. Run positive and negative controls d. No heat inactivation necessary c. Positive test: visible agglutination e. Black clumps form in reactive test d. Detects serum IgM f. False positives - same as VDRL 5. Confirmatory test: Anti-cyclic citrullinated p eptide assay (anti-CCP) a. Used to confirm positive RF tests REMEMBER! b. ELISA technique c. High sensitivity and specificity Do NOT Refrigerate d. Allows earlier diagnosis and earlier Specimen for Cold treatment which may reduce joint erosion and deformity Agglutinin Assay Antibody will bind to red cells leaving serum free of antibodies and result in a false negative or decreased cold agglutinin titer. Screening and Con.irmatroy Test for RA 44 CELIAC DISEASE (CELIAC SPRUE) EBV Antibodies 1. Hypersensitivity to gliadin (a protein component of gluten) found in grains EBV Antibodies such as wheat, barley, rye C 0 2. Laboratory findings ~.... a. Tissue transglutaminase antibody c , -0 0 b. Endomysial antibody (EMA-IgA).0 Anti-EBNA c. Antigliadin antibody (AGA-IgG,.E