the test device, the colored HCV specific recombinant antigen-colloidal gold conjugate complexes with HCV

 

6. The reusable glass slide should be first immersed in

sodium hypochlorite 5% solution and then rinsed with

tap water and then distilled water. Wipe thoroughly

dry before use.

7. As the biggest risk to laboratory personnel is from

uncharacterized random samples, it is strongly

recommended that as a safety measure hand gloves

should be worn during the entire test procedure.

8. Samples that are contaminated, hemolyzed, lipemic

or highly icteric may give nonspecific reactions.

ONE-STEP TEST FOR HBsAg VIRUCHECK DEVICE

(Courtesy: Tulip Group of Companies) (dipstick method

also available)

Principle

Virucheck one-step test for HBsAg utilizes the principle

of immunochromatography, a unique two-site immuno -

assay on a membrane. As the test sample flows through the

membrane assembly within the test device, the colored antiHBsAg colloidal gold conjugate complexes with HBsAg in

the sample. This complex moves further on the membrane

to the test region where it is immobilized by the anti-HBsAg

antiserum coated on the membrane leading to formation

of a pink colored band which confirms a positive test result.

Absence of this colored band in the test region indicates a

negative test result. The unreacted conjugate and unbound

complex if any move further on the membrane and are

subsequently immobilized by the antimouse antiserum

coated on the membrane at the control region, forming a pink

band. This control band serves to validate the test results.

Reagents and Materials Supplied

Each individual pouch contains:

1. Test device: Contains membrane assembly predispensed with anti-HBsAg antiserum-colloidal gold

conjugate and anti-HBsAg antiserum and antimouse

antiserum coated at the respective regions.

2. Disposable plastic dropper.

Storage and Stability

The sealed pouches in the test kit may be stored between

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

pouch.

Note

1. For in vitro diagnostic use only. Not for medicinal use.

2. Do not use beyond expiry date.

3. Read the instruction 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 the patient is necessary prior to

collection by approved techniques. Though fresh serum/

plasma is preferable, serum/plasma specimen may be

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

testing. Do not use hemolyzed, turbid or contaminated

samples. Turbid samples must be centrifuged and clear

supernatant must be used for testing.

Testing Procedure and Interpretation of Results

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.

Refrigerated specimens must be brought to room

temperature prior to testing.

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

(Fig. 22.27):

Negative

Only one colored band appears on the control region ‘C’.

Serology/Immunology 665

Positive

 In addition to the control band, a distinct colored band

also appears on the test region ‘T’.

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 HBsAg in

the specimen, positive results may start appearing as

early as 2 minutes, negative results must be confirmed

only at the end of 15 minutes.

6. In case of doubtful result at 15 minutes, the test may be

extended up to 30 minutes to get a clear background.

Limitation of the Test

1. Presence of elevated levels of other antigens such

as RF and cross reacting autoantibodies such as

antibodies to HLA DR4 may yield false positive results.

This may occur in less than 1% of the specimens. For

confirmation of results, a confirmatory test must be

used.

2. This test detects the presence of HBsAg in the specimen

and hence should not be used as the sole criterion for

the diagnosis of hepatitis infection.

3. As with all diagnostic test, the results must be

correlated with clinical findings.

HCV FLAVICHECK DEVICE

Courtesy: Tulip Group of Companies

One-Step Immunochromatographic

Test for HCV Antibodies

Introduction

Flavicheck-HCV is a rapid self-performing, third

generation, qualitative one-step, two-site sandwich

immunoassay for the detection of antibodies specific to

the hepatitis C virus in human serum and plasma. The test

employs recombinant proteins derived from the core, NS3,

NS4, and NS5 regions of the HCV genome. Combination

of these proteins in a double antigen sandwich system

not only affords antibody detection to greater number

of HCV-encoded epitopes but also earlier detection of

seroconversion following HCV infection.

Summary

Hepatitis C virus (HCV) is a single-stranded RNA virus of

the Flaviviridae family. The HCV is now known to be the

causative agent for most, if not all non-A, non-B hepatitis

(NANBH). Antibodies to the hepatitis C encoded antigens

are prevalent in the sera of HCV infected individuals.

Detection of these antibodies indicates exposure to the

hepatitis C virus.

Principle

Flavicheck-HCV utilizes the principle of lateral flow

immunochromatography, a unique two site double

antigen sandwich immunoassay on a membrane. As the

test specimen flows through the membrane assembly of

the test device, the colored HCV specific recombinant

antigen-colloidal gold conjugate complexes with HCV

antibodies in the sample. This complex moves further on

the membrane to the test region ‘T’ where it is immobilized

by the HCV specific recombinant antigens coated on the

membrane leading to formation of a colored band which

confirms a positive test result. Absence of this colored

band in the test region indicates a negative test result.