Serology (pics) Flashcards
Indirect/Double Layer Immunofluorescent Assay
FA test for rabies
**Left: (+)FA test is due to the presence of fluorescence; Right: (-) FA test due to the absence of fluorescence
Indirect/Double Layer Immunofluorescent Assay
FTA-ABS
**Fluorescent treponemal antibody absorption test (FTA-ABS) showing a positive result for syphilis
DIFF. PATTERNS FOR ANTI-NUCLEAR ANTIBODIES (ANA)
THE “RIM/PERIPHERAL” PATTERN
DIFF. PATTERNS FOR ANTI-NUCLEAR ANTIBODIES (ANA)
THE “SPECKLED” PATTERN
DIFF. PATTERNS FOR ANTI-NUCLEAR ANTIBODIES (ANA)
THE “NUCLEOLAR” PATTERN
Enzyme-linked Immunosorbent Assay (ELISA)
Antigen is attached to bottom of well => Patient’s serum is added. If antibodies to the antigen are present, they will bind to antigen. Plate is washed. => antihuman globulin (AHG) with enzyme attached is added. Plate is again washed. AHG will remain only if antibody is present. => Substrate of enzyme is added. If enzyme is present, a colored product will be formed. Color indicates the antibody is present. (The intensity of the color is directly proportional to the amount of substance)
Reaction for Clostridium difficile testing
Use diluted specimen (ex watery stool), then add the conjugate then the substrate, and lastly the stopping or colored solution
Radial Immunodiffusion Method
Specific antibody is incorporated into the agar gel and wells are cut to contain the antigen
A ring of precipitation (dotted line) forms around a well that contains the corresponding antigen
The higher the concentration of the antigen, the larger the ring (diameter) of precipitation
Ouchterlony Technique
The patient’s serum is in the center well. B and C are reactive with the patient’s serum. A, D, and E are non-reactive.
Double Diffusion, Double Dimension (Ouchterlony Technique)
Three patterns:
a. Identity – forming smooth curve; antigen in the sample is same with known antigen
b. Partial Identity – precipitation line merge with spur formation (like the leg of rooster); antigen in the sample has some similarities with the known antigen
c. Non-identity – precipitation lines cross and intersect; antigen in the sample is different from known antigen
Ouchterlony Technique
Wells are cut into an agar surface and a drop of the patient’s serum is placed into the center well. Solutions of known antigens are placed into the peripheral wells. Antibodies from the patient’s serum diffuse outward from the center cell as do the antigens from their individual wells. In the above example, the serum has antibodies to antigens C and H since there are precipitate lines formed.
One HA unit: minimum amount of virus that causes complete agglutination of RBCs
Complement Fixation Test. Complement causes lysis of the RBCs. (+) Reaction = no hemolysis because complement has been bound (fixed) by the reaction between antigen and antibody. (-) Reaction = hemolysis because no antibody was present to bind with the antigen. Complement was therefore not fixed and was available to lyse the RBCs.
Procedure for CRP serologic testing
Procedure for Latex ASO reaction
Semiquantitative latex ASO reaction
Immunodiffusion Test. For latex ASO procedure. Inoculate and measure the zone
Western blot procedure. The usual blots are gp41 and p24 antigen.
level of antigen and antibody in certain time period. The HIV antigen will only be present up to less than 3 months. But the antibodies (gp41 and p24) will be present up to more than 3+ years. Note also the presence of blot in the gp41 and p24 in the immunoblot analysis which is indicative of HIV.
Heartworm antigen test for Dirofilaria immitis.
Procedure is same with the human. We have a C (control) and T (test). To be valid, the bar must be present in C to identify that there really is a control. This procedure employs Lateral Chromatography.
