Serologic application/tests Flashcards by PATRICIA ONG

SEROLOGIC TESTS FOR SYPHILIS: Used to detect Reagin (a substance present in the serum of
individuals with certain diseases including syphilis)

Nontreponemal Method

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Uses heated serum (56ºC for 30 min.) as specimen and result is read microscopically

VDRL (VENEREAL DISEASE RESEARCH LABORATORY TEST)

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FLOCCULATION – The agglutination of lipoidal
particles/substanced

VDRL

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VDRL: To inactivate the complement protein in the
serum

Heating

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VDRL: Rgt Ag: colorless alcoholic solution containing

Cardiolipin, Lecithin, Cholesterol,

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Serves as the reagent; detects reagin (anti-cardiolipin)

Cardiolipin

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Rotator for VDRL

180 rpm for 40 min

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VDRL result for: SLE (Systemic lupus), Rheumatic fever, IM (Infectious mononucleosis), Malaria, Pregnancy

False Positive

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VDRL is highly sensitive for

CSF

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Uses unheated serum as specimen and result is read macroscopically

RPR (RAPID PLASMA REAGIN)

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RPR (RAPID PLASMA REAGIN) uses ___ to modify the basic VDRL Ag

Choline-chloride

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RPR Reagents: colorless alcoholic solution

Cardiolipin, Lecithin, Cholesterol, and Charcoal

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used as the carrier for the antigen cardiolipin for RPR

charcoal

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Rotator for RPR

100 rpm for 8 mins

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False (+) RPR results in

IM, Leprosy, RA (Rheumatoid arthritis)

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Ag dispenser: 18
Volume: 1/60 mL
Speed rpm: 180
Time (min): 4 mins

Serum VDRL Screening Qualitative

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Ag dispenser: 19
Volume: 1/75 mL
Speed rpm: 180
Time (min): 40 mins

Serum VDRL Quantitative Titer measurement - tube method

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Ag dispenser: 22/23
Volume: 1/100
Speed rpm: 180
Time (min): 8

CSF-VDRL
(screening for
neurosyphilis)

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Ag dispenser: 20
Volume: 1/60
Speed rpm: 100
Time (min): 8

RPR rapid testing

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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

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Syphilys Screening Test:

BIOLOGIC FALSE NEGATIVE (↓ SENSITIVITY)

Too early infection
Immune tolerance
Alcohol intake
Inactive/Latent state of infection
Non reactivity due to treatment

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Most Specific Test For Syphilis; antigen used is the live actively motile
treponemes

TPI Immobilization Test

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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

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End product for TPI

Dead treponeme (immobilized)

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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