Serologic application/tests Flashcards
SEROLOGIC TESTS FOR SYPHILIS: Used to detect Reagin (a substance present in the serum of
individuals with certain diseases including syphilis)
Nontreponemal Method
Uses heated serum (56ºC for 30 min.) as specimen and result is read microscopically
VDRL (VENEREAL DISEASE RESEARCH LABORATORY TEST)
FLOCCULATION – The agglutination of lipoidal
particles/substanced
VDRL
VDRL: To inactivate the complement protein in the
serum
Heating
VDRL: Rgt Ag: colorless alcoholic solution containing
Cardiolipin, Lecithin, Cholesterol,
Serves as the reagent; detects reagin (anti-cardiolipin)
Cardiolipin
Rotator for VDRL
180 rpm for 40 min
VDRL result for: SLE (Systemic lupus), Rheumatic fever, IM (Infectious mononucleosis), Malaria, Pregnancy
False Positive
VDRL is highly sensitive for
CSF
Uses unheated serum as specimen and result is read macroscopically
RPR (RAPID PLASMA REAGIN)
RPR (RAPID PLASMA REAGIN) uses ___ to modify the basic VDRL Ag
Choline-chloride
RPR Reagents: colorless alcoholic solution
Cardiolipin, Lecithin, Cholesterol, and Charcoal
used as the carrier for the antigen cardiolipin for RPR
charcoal
Rotator for RPR
100 rpm for 8 mins
False (+) RPR results in
IM, Leprosy, RA (Rheumatoid arthritis)
Ag dispenser: 18
Volume: 1/60 mL
Speed rpm: 180
Time (min): 4 mins
Serum VDRL Screening Qualitative
Ag dispenser: 19
Volume: 1/75 mL
Speed rpm: 180
Time (min): 40 mins
Serum VDRL Quantitative Titer measurement - tube method
Ag dispenser: 22/23
Volume: 1/100
Speed rpm: 180
Time (min): 8
CSF-VDRL
(screening for
neurosyphilis)
Ag dispenser: 20
Volume: 1/60
Speed rpm: 100
Time (min): 8
RPR rapid testing
Syphilys Screening Test:
BIOLOGIC FALSE POSITIVE (↓ Specificity)
Malaria
Systemic Lupus Erythematosus
Rheumatoid Arthritis
Hepatitis
Infectious Mononucleosis
Leprosy
Pneumonia
Trypanosomiasis
Scarlet Fever
Rickettsial disease
Aging
Drug addiction
Pregnancy
Syphilys Screening Test:
BIOLOGIC FALSE NEGATIVE (↓ SENSITIVITY)
Too early infection
Immune tolerance
Alcohol intake
Inactive/Latent state of infection
Non reactivity due to treatment
Most Specific Test For Syphilis; antigen used is the live actively motile
treponemes
TPI Immobilization Test
Anti-T.pallidum (ab) binds with the live treponemes
(ag) and forms an ag-ab complex, which activates the classical complement pathway (C56789) that lyses the live treponeme’smembrane
TPI Immobilization Test
End product for TPI
Dead treponeme (immobilized)
Positive reaction of TPI
Immobilization of >50% of live treponeme
Reagent antigen for TPI
Live actively motile treponemes from lesions of infected rabbit testicle
Antibody of TPI
Patient’s syphilitic serum
Source of Complement for TPI
Guinea pig serum
Commonly used confirmatory test for syphilis
FTA-ABS (FLUORESCENT TREPONEMAL ANTIBODY
ABSORPTION TEST)
FTA-ABS Principle uses:
Indirect immunofluorescence test – Uses FITC as
fluorescent probe
FTA-ABS Reagent antigen:
Dead T.pallidum strain (Nichol’s strain) –
fixed on a slide
Antibody for FTA-ABS
Patient’s syphilitic serum
Absorbet of FTA-ABS
Reiter treponeme
Syphilis: Used to block the group ab so that the specific pathogenic ab are the ones being tested
Reiter treponeme
Conjugate of FTA-ABS
Fluorescent label AHG
2nd preferred confirmatory test for syphilis
TPHA (T. PALLIDUM HEME AGGLUTINATION)
Principle of TPHA (T. PALLIDUM HEME AGGLUTINATION)
Heme agglutination (RBC clumping)
Carrier of T. pallidum antigen in TPHA
RBC
Reagent antigen of TPHA
Glutaraldehyde stabilized turkey RBC coated
with treponemal antigen
Antibody for TPHA
Px’s syphilitic serum
The positive reaction of TPHA
RBC clumping
Principle of MHA-TPA (MICRO HEMEAGGLUTINATION T. PALLIDUM TEST)
heme agglutination
Reagent for MHA TPA
Tanned formalin sheep RBC coated with Treponeme antigen
Antibody for MHA-TPA
Patient’s syphilitic serum
MHA TPA positive reaction
RBC clumping
Test for pxs who receive adequate treatment during 1º or 2º stage yet fail to exhibit a decrease or reversion of serologic test results and show Reactive results indefinitely
Seroresistant / Wasserman fast
presence indicates recent infection with Streptococcus pyogenes (Group A streptocci)
ANTI-STREPTOLYSIN O (ASO)
Manifestations of S. pyogenes infection
Upper respiratory infection – Pharyngitis (Sore
throat)
Scarlet fever
Skin infection – Cellulitis, Impetigo, Erysipelas
A phenomenon whereby immune response directed against one antigen can be extended to include
activity against other closely related
antigens
Molecular mimicry
S. pyogenes ab & Myocardial ag are closely related (similar) – When the body produces an antigen against S. pyogenes, it will attack the heart
(myocardial ag) instead due to Molecular
mimicry
Cross reactivity
Complications/Sequelae of S. pyogenes infection
Acute Rheumatic Fever
Poststreptococcal Glomerulonephritis
Bacterial toxin released during S. pyogenes infection
STREPTOLYSIN O
Streptolysin O
In its active form ________ form, it can lyse rbcs (hemolysis)
Reduced
Neutralization reaction: estimates the amount of antibody in the presence of a constant dose of SLO can completely inhibit hemolysis of a constant given number of red cells
ASO titration
Reciprocal of the highest dilution showing ________ in ASO titer
no hemolysis
ASO titer is expressed in __________
Todd units
Principle of Rapid Latex Agglutination
Passive agglutination
Positive reaction in Rapid Latex Agglutination
Agglutination ≥ 200 units per mL
serologic test used for the detection of streptococcal enzyme
Streptozyme
Reagent in streptozyme
RBC horse
Antigen of Streptozyme
Artificially attached to RBC
Antigens of Streptozyme
DNAse, Streptokinase, Hyaluronidase, NADase,
Streptolysin O (Oxidized; non hemolytic form)
Calor
Heat
Rubor
Redness
Dolor
Pain
Tumor
Swelling
Functio laesa
Diminished function
Test for Myocardial Infarction
CRP along with CK-MB
Most popular of CRP tests and is claimed to be the most sensitive
RAPID LATEX AGGLUTINATION TEST
Elevated level: 0.6 mg/dL; indicates
Inflammation
Tissue damage
Elevated CRP is seen in:
Bacterial and viral infections
Rheumatic diseases such as RA
Myocardial infarction
Burn injuries
Tuberculosis
Renal transplantation
Malignancies
COLD AGGLUTININS
IgM
antibodies that react best with RBCs at temperature <37℃
Cold Agglutinins
IgM is inactive in ____ temp
Normal body temp
In vitro: IgM is optimally observed at ref tem
0-4 deg C
In vivo: IgM activity is seen at
30℃
IgM reaction strength is often greatest at
0 to 4 deg C
A condition where there is high titer of cold agglutinin (IgM) causing intravascular agglutination when the body is exposed to the cold
COLD AGGLUTININ SYNDROME (CAS)
Primary Atypical Pneumonia - M.pneumoniae
(community acquired/walking pneumonia) CAS:
Abnormal cold IgM abs with Anti-I specificity
CAS in Infectious Mononucleosis (Epstein-barr virus)
Cold autoantibody with Anti-i specificity
RAPID SCREENING TEST FOR COLD AGGLUTININS Principle:
Hemeagglutination
Antigen for Rapid screening test of Cold Agglutinins
Cold agglutinins in patient’s serum
Tubes are incubated at ____ for ______ overnight
t 4ºC for 18-24 hours
If IgM is ↑ it produces in Rapid screening test
agglutination
Positive result for cold agglutinins
No hemagglutination at 37℃
Hemagglutination at 4℃
Negative result for cold agglutinins
No hemagglutination at 37℃
No hemagglutination at 4℃
antibodies demonstrated in patient with increased bacterial infection that are manifested by high fever
Febrile agglutinins
Febrile agglutinins screening test
rapid slide test
confirmatory test for febrile agglutinins
tube test
Best time to collect sample in febrile agglutinins
Height of fever
Peak titer may occur during in febrile agglutinins
convalescence
INFECTIOUS MONONUCLEOSIS: – Used for any substance that stimulated the formation of sheep hemolysin (Antisheep cells)
Forssman antigen
Antibodies produced by unrelated species which can cross-react with the same antigen
Heterophil antibodies
Reacts with Sheep cells, Ox(Beef) cells, and Horse cells
Does not react with Guinea pig cells
Not Forssman in nature
Heterophil Antibodies in IM
Reacts with Guinea pig cells, Sheep cells, and Horse
cells
Does not react with Ox(Beef) cells
Heterophil Antibodies of Forssman
Reacts with Sheep cells, Ox(Beef) cells, Horse cells,
and Guinea pig cells
Heterophil Antibodies in Serum Sickness
Differential test for IM and Forssman uses
Guinea pig cell and
Ox(Beef) cell
Presumptive/screening test for antibodies that are heterophil in nature
PAUL BUNNEL TEST
DAVIDSON DIFFERENTIAL TEST antigen
: Guinea pig kidney cell and Ox(Beef) rbc
PAUL BUNNEL TEST antigen
2% suspension of sheep rbc
Absorption-Hemagglutination for IM
DAVIDSON DIFFERENTIAL TEST; MONOSPOT