Testing Procedure and Interpretation of Results

Bring kit components, specimen to room temperature

prior to testing.

1. Bring the sealed pouch to room temperature, open

the pouch and remove the device. Once opened, the

device must be used immediately.

2. Dispense two drops of serum/plasma specimen into

the sample well ‘S’ using the dropper provided.

3. At the end of 15 minutes, read the results as follows:

 Negative: Appearance of only one pink to deep purple

colored band at the control region ‘C’ (Fig. 22.26).

 Positive: In addition to the control band, a distinct

pink to deep purple colored band also appears on the

test region ‘T’ (Fig. 22.26).

FIG. 22.26: Syphicheck reading

624 Concise Book of Medical Laboratory Technology: Methods and Interpretations 4. The test should be considered invalid if neither the test

band nor the control band appear. Repeat the test with

a new device.

5. Although, depending on the concentration of

Treponema antibodies in the specimen, positive results

may appear as early as 2 minutes, negative results must

be confirmed only at the end of 15 minutes.

Remarks

1. Syphicheck detects the presence of Treponema

antibodies; thus, a positive result indicates a past or

present infection. Positive results should be evaluated

in correlation with the clinical condition before

arriving at a final diagnosis.

2. Low levels of antibodies to Treponema pallidum such as

those present at a very early primary stage of infection

can give a negative result. But a negative result does not

exclude the possibility of exposure to or infection with

Treponema pallidum. Retesting is indicated after two

weeks if clinically syphilis is still suspected.

3. In order to assess the clinical response to treatment,

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.

THIRD GENERATION DOUBLE ANTIGEN

SANDWICH ENZYME LINKED

IMMUNOSORBENT ASSAY (ELISA) FOR THE

DETECTION OF ANTIBODIES TO TREPONEMA

PALLIDUM IN HUMAN SERUM OR PLASMA

TREPOLISA 3.0

(Courtesy: Tulip Group of Companies)

Trepolisa 3.0

Trepolisa 3.0 is intended to be used for the detection of

total antibodies (i.e. IgG, IgM, IgA, etc.) to Treponema

pallidum in human serum or plasma.

Summary and Explanation

Syphilis is a sexually transmitted (venereal) disease caused

by the spirochete Treponema pallidum. The disease can

also be transmitted congenitally thereby attaining its

importance in antenatal screening. After infection the host

forms non-treponemal anti-lipoidal antibodies (regains) to

the lipodal 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 test. Test for treponema specific

antibodies such as TPHA, FTA-ABS, rapid treponema

antibody tests and ELISA are gaining importance as

screening as well as confimatory tests because they detect

the presence of antibodies specific to Treponema pallidum.

Principle of the Assay

Microwell strips are coated with recombinant

47 Kd and 17 Kd antigens. The same antigens are

conjugated to HRP. Samples along with positive and

negative controls are added in the coated wells and

incubated simultaneously with antigen HRP conjugate.

The wells are washed to remove unbound components.

Captured antibodies are detected by adding substrate.

The reaction is stopped after specified time with acid and

absorbance is determined for each well at 450 nm with an

ELISA reader. The cutoff value is calculated by the given

formula and absorbances of all the wells are compared

with the cutoff value. Any sample having absorbance more

than the cutoff value is considered reactive.

TESTS FOR TYPHOID/ENTERIC FEVER

WIDAL ANTIGEN SET/ANTIGENS FOR TUBE

TESTS (TYPHOCHEK)

(Courtesy: Tulip Group of Companies)

Summary

Enteric fever occurs when pathogenic microorganisms like

S. typhi, S. paratyphi A, S. paratyphi B infect the human

body. During the course of disease, the body responds to

this antigenic stimulus by producing antibodies whose

titer rises slowly in early stages, to a maxima and then

slowly falls till it is undetectable. Antibodies to Salmonella

organisms may be detected in the patient serum from

the second week after onset of infection. Information

regarding the titers and whether or not they are rising or

falling can be obtained by performing serological tests

using Typhochek widal antigen suspensions.

Reagent

Typhochek contains ready-to-use colored, smooth antigen

suspensions of the bacilli; S. typhi ‘O’, S. typhi ‘H’, S. paratyphi

‘AO’, S. paratyphi ‘BO’, S. paratyphi ‘AH’, S. paratyphi ‘BH’.

Typhochek reagents are versatile and standardized for

use in a standard tube test procedure for the detection of S.

typhi and S. paratyphi antibodies in the patient’s serum.