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SEROLOGICAL DIAGNOSIS OF SYPHILIS

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Serological diagnosis of syphilis skill based learning l.jpg

Serological Diagnosis of SyphilisSkill Based Learning

Dr.T.V.Rao MD

Dr.T.V.Rao MD


Syphilis l.jpg

Syphilis

"He who knows syphilis, knows medicine"

Sir William Osler

Dr.T.V.Rao MD


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Syphilis was a Taboo

  • Poster for testing of syphilis, showing a man and a woman bowing their heads in shame (ca. 1936).

Dr.T.V.Rao MD


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SYPHILISINTRODUCTION

  • Caused by Treponema pallidum.

  • Transmission: sexual; maternal-fetal, and rarely by other means.

  • Primary and secondary syphilis in the US dropped by ~ 90 %t from 1990 to 2000, the number of cases have gone up since then.

  • A dramatic increase in cases in men from 2000 to 2002 reflected syphilis in MSM.

  • Syphilis increases the risk of both transmitting and getting infected with HIV.

    Perform HIV testing in all patients with syphilis.

Dr.T.V.Rao MD


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Introduction to Syphilis

  • Syphilis is one of a group of diseases caused by spirochete organisms of the genus Treponema. Sexually acquired syphilis occurs worldwide and is caused by T. pallidum subspecies pallidum.

Dr.T.V.Rao MD


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Other Related to Treponemes

  • Related Treponemes cause the non-venereal treponematosesbejel, or endemic syphilis (T. pallidum endemicum), yaws (T. pallidum pertenue), and pinta (T. carateum).

Dr.T.V.Rao MD


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STAGES OF SYPHILIS

  • Primary

  • Secondary

  • Latent

    • Early latent

    • Late latent

  • Late or tertiary

    • May involve any organ, but main parts are:

      • Neurosyphilis

      • Cardiovascular syphilis

      • Late benign (gumma)

  • Dr.T.V.Rao MD


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    Diagnosis of Syphilis

    • The nontreponemal tests, VDRL and rapid plasma reagent (RPR), are antilipoidalantibodies seen in other disease states, pregnancy, and occasionally after vaccination. They are nonspecific and cannot rule in disease. These tests have sensitivities approaching 80% in patients with symptomatic primary syphilis and virtually 100% in patients with secondary syphilis.

    • – A positive VDRL/RPR should be quantified and titers followed at regular intervals after treatment. As such, its value is in response to treatment. However, it does not correlate with symptom resolution.

    • – Most patients have nonreactive nontreponemal tests within several years after successful treatment for syphilis, but a significant number have persistently positive tests, the so-called serofast reaction.

    Dr.T.V.Rao MD


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    Diagnosis

    Laboratory Diagnosis

    • Identification of Treponema pallidum in lesions

      • Darkfield microscopy

      • Direct fluorescent antibody - T. pallidum (DFA-TP)

    • Serologic tests

      • Nontreponemal tests

      • Treponemal tests


    Nontreponemal serologic tests continued l.jpg

    Advantages:

    Rapid and inexpensive

    Easy to perform and can be done in clinic or office

    Quantitative

    Used to follow response to therapy

    Can be used to evaluate possible reinfection

    Disadvantages:

    May be insensitive in certain stages

    False-positive reactions may occur

    Prozone effect may cause a false-negative reaction (rare)

    Diagnosis

    Nontreponemal Serologic Tests (continued)


    Diagnosis l.jpg

    Diagnosis

    • Patients with a reactive VDRL or RPR should have the result confirmed by specific treponemal testing. FTA-ABS and or EIA.

    • • Tertiary syphilis Serology is used in the diagnosis. Evaluation of neurosyphilis requires a lumbar puncture (LP) and evaluation of the CSF.

    • – The CDC currently recommends LP only if the patient is seroreactive and HIV positive, has symptoms of neurosyphilis

    Dr.T.V.Rao MD


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    Tests to Confirm

    • Syphilis may be confirmed either via blood tests or direct visualization using microscopy. Typical diagnosis is with blood tests using nontreponemal and/or treponemal tests. Nontreponemal test are used initially and include venereal disease research laboratory (VDRL) and rapid plasma regain however as these test occasionally are falsely positive confirmation is required with a treponemal test such as treponemal pallidum particle agglutination (TPHA) or fluorescent treponemal antibody absorption test (FTA-Abs)

    Dr.T.V.Rao MD


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    The VDRL Testing Procedure

    Dr.T.V.Rao MD


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    VDRL - Background

    • The Venereal Disease Research Laboratory (VDRL) test is one of two variations of flocculation procedures used for serological testing of syphilis, the other being the Rapid Plasma Reagin (RPR). Flocculation testing is based on antibody detection with the interaction of soluble antigen with an antibody that results in a precipitate formation of fine particles.

    Dr.T.V.Rao MD


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    VDRL Test Basics

    • The VDRL is a confirmatory serological micro flocculation slide test used for the detection of syphilis antibodies. In a VDRL procedure, the patient’s serum is heat-inactivated and mixed with a buffered saline suspension of VDRL Antigen containing cardiolipin, lecithin and cholesterol that binds with Reagin, an antibody-like protein. A combination of Reagin and VDRL Antigen form microscopic clumping called flocculation.

    Dr.T.V.Rao MD


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    VDRL – A Standard Test for Syphilis

    • The VDRL can be used for qualitative and quantitative measurements and is recommended when a patient suspected of having syphilis has a negative dark field microscopy result or when atypical lesions are present.

    Dr.T.V.Rao MD


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    VDRL Serological Procedure Principles

    • VDRL Antigen is a nontreponemal antigen composed of cardiolipin cholesterol and lecithin. The nontreponemal tests measures anti-lipid antibodies, which are formed by the host in response to lipids released from damaged host cells early in infection with T. pallidum, and lipid-like material form the treponemal cell surface. During syphilis infection, an antibody-like substance called reagin can be detected in the patient’s serum or CSF.

    Dr.T.V.Rao MD


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    Preparation of Antigen

    • Prepare a fresh antigen suspension each testing day. Once prepared, it should be used within 8 hours.

    • Store prepared suspension at 23-29)C.

    • Test antigen suspension reactivity with control sera (Reactive, Weakly reactive and Nonreactive). Test serum dilutions within 1 hour after heat inactivation.

    • Use antigen suspension only if it produces the expected reactivity with the control sera comparable to results obtained with the reference antigen.

    Dr.T.V.Rao MD


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    Required Materials

    • VDRL Antigen with buffered saline solution containing 1% sodium chloride, pH 6.0+/-0.1 with 0.05% formaldehyde preservative

    • Reactive, weakly reactive and nonreactive serum

    • 0.9% saline, non-disposable 1cc glass syringe and calibrated needles without bevel-18 gauge(serum) or 21-22 gauge(CSF), slide cards(serum) or concavity slides(CSF)

    • Stirrers

    • Rotator

    Dr.T.V.Rao MD


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    Specimen Collection and Preparation for Serum

    • Collect 5-8 ml of blood by aseptic venipuncture in a red top tube.

    • Allow blood to clot at room temperature then centrifuge to obtain serum.

    • Heat the test sera at 560C for 30 minutes.

    • Specimen must be at 23-290C when tested.

    • Specimen must be clear of hemolysis and show no visible evidence of bacteria contamination.

    • Store at room temperature for 4 hours, after which store at 2-80C, maybe refrigerated up to 5 days, then frozen at <-200C.

    Dr.T.V.Rao MD


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    Specimen Collection and Preparation for CSF

    • Centrifuge and decant the specimen

    • Specimens do not require heat inactivation before testing.

    • Spinal fluids that are visibly contaminated or that contain gross blood are unsatisfactory

    Dr.T.V.Rao MD


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    Antigen Suspension Preparation

    • Pipette 0.4ml of VDRL buffered saline to the bottom of a round 30 ml glass stoppered bottle with a flat inner-bottom surface. Gently tilt bottle so that VDRL buffered saline will cover the entire inner-bottom surface of the bottle.

    • Add 0.5 ml of VDRL Antigen directly into the saline while continuously but gently rotating the bottle on a flat surface from the lower half of a 1.0 ml pipette graduated cylinder to the tip. Add antigen drop by drop at a rate that allows about 6 sec for 0.5 ml of antigen. Keep pipette tip in the upper third of the bottle and do not splash saline unto the pipette.

    Dr.T.V.Rao MD


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    Antigen Suspension Preparation

    • Expel the last drop of antigen without touching pipette to the saline and continue rotation of the bottle for 10 sec.

    • Add 4.1 ml of buffered saline from a 5 ml pipette. Do not drop saline directly on antigen; allow it to flow down the side of the bottle.

    • Cap the bottle and mix by gentle inversion. Allow to stand for 5 minutes but no more than 2 hours. The suspension is ready for use.

    • Remix suspension by swirling only

    Dr.T.V.Rao MD


    Antigen suspension l.jpg

    Antigen Suspension

    • Cap the bottle and mix by gentle inversion. Allow to stand for 5 minutes but no more than 2 hours. The suspension is ready for use.

    • Remix suspension by swirling only

    Dr.T.V.Rao MD


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    Procedure: Step 1

    Wells should be labeled as reactive ®, weakly reactive (WR), and nonreactive (NR),

    Dr.T.V.Rao MD


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    Procedure: Step 3

    Add one drop (.01 ml) of sensitized antigen suspension to each specimen with a 21 or 22 gauge needle.

    Dr.T.V.Rao MD


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    Procedure: Step 4

    • Rotate slides for 8 minutes on a mechanical rotator at 180 rpm. Note: when the tests are performed in a dry climate, the slides may be covered with a box lid to prevent evaporation.

    Dr.T.V.Rao MD


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    Results for Serum Specimen

    • Qualitative Testing - Medium to large clumps (Reactive); Small clumps (Weakly Reactive); No clumping or very slight roughness (Nonreactive).

    • Verify control sera results for expectation. If reactions are not as expected, the test is invalid and results can not be reported.

    Dr.T.V.Rao MD


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    Reporting the Results

    • Perform a quantitative test to endpoint on all serum samples that produce reactive, weakly reactive or “rough” nonreactive results in the qualitative slide test.

    • Quantitative Testing - Report the titer as the highest dilution that produces a Reactive (not weakly reactive) results

    Dr.T.V.Rao MD


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    Diagnosis

    Diagnosis of CNS Infection with Syphilis

    No test can be used alone to diagnose neurosyphilis.

    • VDRL-CSF: highly specific but insensitive

    • Diagnosis usually depends on the following factors:

      • Reactive serologic test results,

      • Abnormalities of CSF cell count or protein, or

      • A reactive VDRL-CSF with or without clinical manifestations.

    • CSF leukocyte count usually is elevated (>5 WBCs/mm3) in patients with Neurosyphilis.

    • The VDRL-CSF is the standard serologic test for CSF, and when reactive in the absence of contamination of the CSF with blood, it is considered diagnostic of Neurosyphilis.


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    Specimen Collection and Preparation for CSF

    • Centrifuge and decant the specimen

    • Specimens do not require heat inactivation before testing.

    • Spinal fluids that are visibly contaminated or that contain gross blood are unsatisfactory

    Dr.T.V.Rao MD


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    TestingCSFSamples

    Quantitative tests are run on all spinal fluids found to be reactive in the qualitative test. Prepare fluid as follows:

    A. Pipette 0.2 ml of 0.9% saline into each of 5 or more tubes.

    Dr.T.V.Rao MD


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    Testing of CSF Samples

    Add 0.2ml of unheated spinal fluid to tube 1, mix well and transfer 0.2 ml to tube 2 .

    Dr.T.V.Rao MD


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    Testing of CSF Samples

    Continue mixing and transferring 0.2 ml from one tube to the next until the last tube is reached. The respective dilutions are 1:2, 1:4, 1:8, 1:16. Etc.,

    Dr.T.V.Rao MD


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    Reporting CSF Samples

    2. Test each spinal fluid dilution and undiluted spinal fluid as described under “VDRL slide qualitative on spinal fluid.”

    3. Report results in terms of the greatest spinal fluid dilution (dils) that produces a reactive result.

    Dr.T.V.Rao MD


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    All Positive Samples tested by Quantitative Method

    • In Quantitative Testing - Report the titer in terms of the highest dilution that produces a reactive (not weakly reactive) result.

    Dr.T.V.Rao MD


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    Quantitative Testing and Reporting

    • In Quantitative Testing- Report the titer in terms of the highest dilution that produces a reactive (not weakly reactive) result.

    Dr.T.V.Rao MD


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    Interpretation

    • Nonreactive VDRL - with clinical evidence may indicate early primary syphilis, a prozone reaction in secondary or late syphilis.

    • Nonreactive VDRL- with no clinical evidence may indicate no current infection or an effectively treated infection.

    • Quantitative VDRL- detects changes in reagin titer. Serum samples displaying a fourfold increase in titer on a repeated sample may indicate an infection, reinfection or treatment failure. A fourfold decrease during treatment indicates adequate therapy.

    Dr.T.V.Rao MD


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    Sources of Error

    • False positive reactions - occur in 10% to 30% of positive serological tests for syphilis and consist of nonsyphilitic positive VDRL. reactions with cardiolipin type antigens.

    • False negative reactions - consist of conditions and a variety of situations.

    • Weakly reactive- caused by very early infection, lessening of the activity of the disease after treatment and improper technique or questionable reagents.

    Dr.T.V.Rao MD


    False positive reactions l.jpg

    Lupus erythematosus

    Rheumatic fever

    Vaccinia and virus pneumonia

    Pneumococcal pneumonia

    Infectious mononucleosis

    Infectious hepatitis

    Leprosy

    Malaria

    Rheumatoid arthritis

    Pregnancy

    Aging individuals

    False Positive Reactions

    Dr.T.V.Rao MD


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    False Negative Reactions

    • Technical error - unsatisfactory antigen or technique.

    • Low antibody titers

    • Presence of inhibitors in the patient’s serum

    • Reduced ambient temperature (below 230 to 290)

    • Prozone reaction

    Dr.T.V.Rao MD


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    RPR test

    The RPR test is a nontreponemal testing procedure for the serologic detection of syphilis.

    Dr.T.V.Rao MD


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    Principle of RPR Test

    • The RPR Card antigen suspension is a carbon particle cardiolipin antigen that detects reagin.

    • Reagin is an antibody like substance present in serum or plasma from individuals with syphilis.

    • The reagin binds to the test antigen which consists of cardiolipin-lecithin coated particles that cause macroscopic flocculation.

    Dr.T.V.Rao MD


    Principle of rpr l.jpg

    Principle of RPR

    • When a specimen such as serum or plasma contains antibody, flocculation occurs with the resulting aggregation of the carbon particles.

    • The flocculation appears as black clumps against the white background of the plastic coated card.

    Dr.T.V.Rao MD


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    Principle of RPR

    • Antibodies associated with syphilis begin to appear in the blood 4 to 6 weeks after infection. Nontreponemal tests determine the presence of reagin. Reagin is a nontreponemal autoantibody directed against cardiolipin antigens.

    Dr.T.V.Rao MD


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    Materials for RPR

    • RPR Test Cards

    • RPR Control Cards

    • RPR Antigen

    • Distilled Water

    • Dispenstirs

    • Rotator

    Dr.T.V.Rao MD


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    RPR Test Background

    • The RPR test uses a white plastic coated card that consist of several circles that are 18 mm in diameter.

    • The controls which are strongly reactive, moderately reactive, and non-reactive are contained on the control card in a dried form.

    Dr.T.V.Rao MD


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    Specimen Collection

    • Unheated Plasma - specimen should be collected with an anticoagulant such as EDTA or heparin, plasma must be stored at 2°C to 8°C. Plasma must be tested within in 24 hrs. of collection

    Dr.T.V.Rao MD


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    *The addition of choline chloride, which inactivates complement enables the serum to be tested without prior heating.

    Unheated serum- centrifuge for sedimentation of cellular elements, serum may be frozen until time of testing.

    Heated Serum- transfer serum to clean tube and place in 56°C water bath for 30 minutes

    Specimen Processing

    Dr.T.V.Rao MD


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    Prepare the Card

    • Label rings on test card with numbers of samples to be tested

    • Use Dispenstir to draw up serum sample.

    • Hold Dispenstir in a perpendicular position directly over the test circle to which the specimen is to be delivered.

    • Squeeze Dispenstir to allow 1 drop to fall on to each circle

    Dr.T.V.Rao MD


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    Performing the Test

    • Invert Dispenstir,and using the sealed end spread the specimen in the confines of the circle.

    • Reconstitute the antigen bottle, by shaking. Holding the bottle in a straight vertical position drop one or two drops in the upper corner of each test circle, then place one “free falling” drop on each test area.

    Dr.T.V.Rao MD


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    Rotate card at Regulated Speed

    • Rotate card for 8 minutes on a mechanical rotator at 100 rpm. The test card she also be covered with a humidifier cover.

    • After rotating mechanically, the test card should be rotated manually by hand 3 to four rotations and then read immediately macroscopically in the “wet” state under a high intensity lamp.

    Dr.T.V.Rao MD


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    Procedure for Controls

    • A. Use Dispensator to draw up distilled water

    • B. Drop 1 drop on the card test circle for each patient sample.

    • C. Invert Dispensator and spread the water in the circle until the dried control is completely reconstituted.

    • D. Add antigen as described for the patients

    • E. Rotate for 8 minutes at 100 rpm

    Dr.T.V.Rao MD


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    Reactions of Controls

    The following reactions should be observed to compare against the test results:

    • Reactive control - characteristic strong clumping.

    • Reactive moderate control - moderate clumping.

    • Non-reactive control - smooth, grayish appearance of unclumped particles

    Dr.T.V.Rao MD


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    Observe for Reactivity

    Dr.T.V.Rao MD


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    A non reactive RPR sample

    Dr.T.V.Rao MD


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    Repeat all Positive Samples after Dilutions

    Dr.T.V.Rao MD


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    Explanation of Results

    • A negative RPR test may indicate one of the following:

      1. The patient does not have syphilis.

      2. The infection is too recent for antibodies to be produced. (Repeated tests should be administered at 1 week, 1 month, and 3 month intervals to establish presence or absence of disease).

      3. The syphilis is latent or inactive

      4. Faulty immunodefense mechanism

      5. Faulty lab techniques

    Dr.T.V.Rao MD


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    Explanation of Results

    • A positive reaction is not conclusive for syphilis. Several conditions produce biologic false positive results for syphilis. (False positive means that the test revealed a positive reaction when it was actually negative).

    • False positives may reveal the presence of other serious diseases.

    Dr.T.V.Rao MD


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    Nontreponemal positive Tests Need Confirmation

    • Nontreponemal antigen tests are not entirely specific for syphilis and do not have satisfactory sensitivity in all stages of syphilis. Whenever the results of a nontreponemal antigen test disagree with the clinical impression, a treponemal antigen test such as the FTA-ABS should be performed.

    Dr.T.V.Rao MD


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    Malaria

    Leprosy

    Relapsing fever

    Infectious Mononucleosis

    Atypical pneumonia

    Viral pneumonia

    Lupus erythematous

    Measles

    pregnancy

    drug abuse

    Non-syphilitic Conditions Giving Biologic False-Positive Results

    Dr.T.V.Rao MD


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    Resolving False Positive RPR Tests

    • False positive RPR tests may be resolved by testing the patient’s serum with a specific treponemal antigen tests.

    Dr.T.V.Rao MD


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    Treponema-Specific Tests for Syphilis

    Dr.T.V.Rao MD


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    Confirmatory Tests for Syphilis

    • Treponemal tests are used to confirm reactive non –treponemal procedures. TPHA testing is now routinely done

    • A positive FTA-ABS test almost always remains positive and therefore is not recommended for monitoring therapy.

    Dr.T.V.Rao MD


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    TREPONEMAL TESTS

    FTA-ABS

    • Used as a confirmatory tests.

    • Sensitivity and specificity high.

      • 85% of patients with primary syphilis are reactive

      • 99% with secondary syphilis

      • > 95% with late syphilis (It may be the only test with a positive result for patients with cardiovascular or neurologic syphilis).

    • Remains reactive for life in most, despite adequate therapy. Only 15-25 % of those treated for primary syphilis may turn negative by 2-3 yrs.

    • False positive in other treponemal diseases (pinta, yaws..) and other spirochete diseases (Lyme, leptospirosis…)

      MHA-TP test (microhemagglutination assay for T. pallidum; agglutination of RBCs to which T. pallidum antigens have been fixed is the basis).


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    TPHA andFTA-ABS Testing are commonly used Confirmatory Tests

    Dr.T.V.Rao MD


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    For Routine Testing a Combination of VDRL or RPR and TPHA is highly preferred

    • TPHA Test is a sensitive passive haemagglutination test, that detects specific Treponema pallidum antibodies in serum within one hour. Used in combination, the VDRL or RPR and TPHA Tests provide accurate and reliable confirmation of active syphilis infection. No specialized equipment is required and results are clearly visible and easily interpreted.

    Dr.T.V.Rao MD


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    Microhemagglutination assay (MHA-TP)and TPHA (T. pallidum hemagglutination assay)

    • The MHA-TP was the earlier iteration of the TPHA. Occasionally, these tests are simply referred to as an indirect hemagglutination assay (IHA). The hemagglutination tests generally are simpler to perform than the fluorescent antibody tests and lend themselves to automation. The MHA-TP and TPHA tests are very rarely used currently. Both tests are quickly being replaced by newer and easier TP-PA and EIA-based tests (see below), including lateral flow strip test

    Dr.T.V.Rao MD


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    Microhemagglutination assay

    • The MHA-TP and TPHA are used to confirm a syphilis infection after another method tests positive for the syphilis bacteria. The MHA-TP and TPHA tests detect antibodies to the bacteria that cause syphilis and can be used to detect syphilis in all stages, except during the first 3 to 4 weeks when antibody levels are too low. These tests are also suitable for use as a screening procedure. Neither of these tests is suitable for use on cerebrospinal fluid (CSF).

    Dr.T.V.Rao MD


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    Principles of TPHA Test

    • TPHA (Treponema Pallidum Hemagglutination) is an indirect hemagglutination assay carried out on micro plates for the qualitative and semi-qualitative detection of anti- Treponema pallidum specific antibodies in human serum. Avian blood cells stabilized and sensitized with a solution of T. pallidum antigen agglutinate in the presence of anti-T Pallidum antibodies, exhibiting a typical agglutination pattern.

    Dr.T.V.Rao MD


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    Reading TPHA Results

    • The upper, left-hand well contains a positive control test. The red cells have had treponemal antigens attached and antibodies in the serum have caused these cells to agglutinate and form a mat across the bottom of the well. These antibodies can be presumed to be specific for Treponemes, since otherwise identical red cells that have not had the treponemal antigens attached do not cause haemagglutination, as seen in the bottom, left-hand well. A negative serum test is shown in the center and a patient's test is on the right. This result supports a diagnosis of syphilis.

    Dr.T.V.Rao MD


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    EIA tests for Syphilis

    • Enzyme immunoassay (EIA), also known as an enzyme linked immunosorbent assay (ELISA), for syphilis is a relatively new invention first appearing on the market in the mid-1990s. There are numerous benefits to the EIA platform over earlier technologies. Firstly, the majority of diseases that are considered to be of clinical and public health importance already exist in an EIA format, which is highly standardized even across international boundaries. This familiarity allows new EIAs to be readily accepted by clinicians and technicians with minimal difficulty. It also limits the need to purchase new capital equipment since most labs will already be equipped to handle EIAs.

    Dr.T.V.Rao MD


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    EIA tests Syphilis Gaining Importance

    • There have been several developments in particularly the advent of enzyme immunoassays(EIAs) and, lately, the commercial availability of recombinant antigen-based tests

    Dr.T.V.Rao MD


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    Fluorescent Treponemal Antibody Absorption (FTA-abs)

    • The FTA-abs test detects antibodies to T. pallidum and can be used to detect syphilis infection at any stage except during the first 3 to 4 weeks after exposure (which is about the same time frame that the VDRL/RPR tests become effective) and in tertiary stages of the disease. In the secondary stage of syphilis, the FTA-abs test is most reliable and is reportedly positive in 100 percent of cases. It can be adapted to detect either IgG or IgM antibody.

    Dr.T.V.Rao MD


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    Gold Standard Confirmatory test

    • The FTA-abs is still generally regarded as the ‘gold standard’, but it has a number of limitations. It is a subjective test and difficult to standardize. It is sensitive, but the TPHA is more sensitive, except in the third and fourth weeks of infection; the TPHA is also more specific2.

    Dr.T.V.Rao MD


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    Sensitivity of Serological Tests in Untreated Syphilis

    *FTA-ABS and TP-PA are generally considered equally sensitive in the primary stage of disease.


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    Diagnosis

    Causes of False-Positive Reactions in Serologic Tests for Syphilis

    *May cause increase in titer in women previously successfully treated for syphilis

    Source:Syphilis Reference Guide, CDC/National Center for Infectious Diseases, 2002


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    AIDS and Syphilis

    • The Serological Tests in AIDS and HIV related infections should be interpreted with caution and expertise, need a better understanding of the progress of the Disease.

    Dr.T.V.Rao MD


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    Nontreponemal Serologic Tests

    • Principles

      • Measure antibody directed against a cardiolipin-lecithin-cholesterol antigen

      • Not specific for T. pallidum

      • Titers usually correlate with disease activity and results are reported quantitatively

      • May be reactive for life

    • Nontreponemal tests include VDRL, RPR, TRUST,


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    References

    • Thomas B. Wiggers, Associate Professor Clinical Laboratory Sciences, UMMC

    • Additional photos:www.Kumc.EDU

    • Center for disease control (1999). Guidelines for evaluation and acceptance of new syphilis serology tests for routine use. US department of health, education and welfare publication, Atlanta.

    • Wasley G.D. (1988). Syphilis serology. Oxford press, New York.

    • Abbot laboratories, Abbott Park, IL 60064.

    Dr.T.V.Rao MD


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    • Created / Designed by Dr.T.V.Rao MD for ‘e’ Learning Resources for Medical and Paramedical Students in the Developing World

    • Email

    • doctortvrao@gmail.com

    Dr.T.V.Rao MD


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