it is advisable to use a reagin test such as VDRL, RPR.

4. Syphicheck detects Treponema antibodies in serum/

plasma; other body fluids may not give accurate results.

5. In immunocompromised patients the test results must

be interpreted with caution.

ONE-STEP TEST FOR SYPHILIS (DEVICE)

SYPHICHECK

(Courtesy: Tulip Group of Companies) (can also be in

dipstick form)

Introduction

Syphicheck is a one-step; rapid, self-performing, qualitative,

two-site double antigen sandwich immunoassay for the

detection of syphilis.

Summary

Syphilis is a sexually transmitted (venereal) disease caused

by the spirochete Treponema pallidum. The disease can

FIG. 22.25: Syphicheck reading

Serology/Immunology 623

also be transmitted congenitally thereby attaining its

importance in antenatal screening. After infection the host

forms non-Treponema antilipoidal antibodies (reagins)

to the lipoidal material released from the damaged host

cells as well as Treponema specific antibodies. Serological

tests for non-Treponema antibodies such as VDRL,

RPR, TRUST, etc. are useful as screening tests. Tests for

Treponema specific antibodies such as TPHA, FTA-ABS,

rapid Treponema antibody tests are gaining importance as

screening as well as confirmatory tests because they detect

the presence of antibodies specific to Treponema pallidum.

Syphicheck qualitatively detects the presence of IgM

and IgG class of Treponema specific antibodies during

syphilis in serum or plasma specimen within 15 minutes.

Principle

Syphicheck utilizes the principle of immunochromatography, a unique two-site immunoassay on a

membrane. As the test sample flows through the membrane

assembly of the test device, the recombinant Treponema

antigen-colloidal gold conjugate forms a complex with

Treponema specific antibodies in the sample. This complex

moves further on the membrane to the test region where

it is immobilized by the recombinant Treponema pallidum

antigen coated on the membrane leading to the formation

of a pink to deep purple colored band at the test region

‘T’ which confirms a positive test result. Absence of this

colored band in test region ‘T’ indicates a negative test

result. The unreacted conjugate and the unbound complex

if any move further on the membrane and are subsequently

immobilized by the anti-rabbit antibodies coated on the

control region ‘C’ of the membrane assembly, forming a

pink to deep purple colored band. The control band serves

to validate the test results.

Reagents and Materials Supplied

Each individual pouch contains:

1. Test device: Membrane assembly predispensed with

recombinant Treponema pallidum antigen-colloidal

gold conjugate, recombinant Treponema pallidum

antigen and anti-rabbit antiserum coated at the

respective regions.

2. Disposable plastic dropper.

3. Desiccant pouch.

Storage and Stability

The sealed pouches in the test kit may be stored between

4 and 30°C for the duration of shelf-life as indicated on the

pouch.

Note

1. Forin vitro diagnostic use only. Not for Medicinal use.

2. Do not use beyond expiry date.

3. Read the instructions carefully before performing the

test.

4. Handle all specimens as potentially infectious.

5. Follow standard biosafety guidelines for handling and

disposal of potentially infective material.

Specimen Collection and Preparation

No special preparation of patient is necessary prior to

specimen collection by approved techniques. Though fresh

serum/plasma is preferable, serum/plasma specimens

may be stored at 2 to 8° C for up to 24 hours, in case of

delay in testing. Do not use hemolyzed or contaminated

specimens. Turbid specimens should be centrifuged or

allowed to settle and only the clear supernatant should be

used for testing.