4. Handle all specimens as potentially infectious.

5. Follow standard biosafety guidelines for handling and

disposal of potentially infective material.

Specimen Collection and Preparation

1. Blood samples collected with a suitable anticoagulant

such as EDTA or Heparin or Oxalate can also be used.

2. No prior preparation of the patient is required before

sample collection by approved techniques.

3. Fresh serum/plasma is preferable. Anticoagulated whole

blood can also be used as specimen. Serum/plasma may

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

testing. For long-term storage, freeze the specimen at

–20°C for 3 months or –70°C for longer periods. Whole

blood should be used immediately and should not be

frozen.

4. Repeated freezing and thawing of the specimen should

be avoided.

646 Concise Book of Medical Laboratory Technology: Methods and Interpretations 5. Do not use hemolyzed, clotted, contaminated,

viscous/turbid specimen.

6. Specimen containing precipitates or particulate matter

must be centrifuged and the clear supernatant only

used for testing.

7. For each sample, a new sample loop should be used.

Testing Procedure and Interpretation of Results

1. Bring the kit components to room temperature before

testing.

2. Open the pouch and retrieve the test device. Once

opened, the device must be used immediately.

3. Label the test device with the patient’s identity.

4. Add 10 µL of serum/plasma or whole blood with a

micropipette into the sample port “A”, OR using the

5 µL sample loop provided with the kit. Dip the loop

into the sample and then blot into the sample port

‘A’. Repeat this step twice for each sample. Ensure

that the loop does not retrieve clots or debris from

the sample.

5. Add 5 drops of sample running buffer to the reagent

port ‘B’.

6. At the end of 15 minutes read the results as follows.

Negative Test Result

Only one colored band appears in the control window ‘C’.

In addition to the band in control window ‘C’, another

red/purple band appears in the test window ‘T’ indicating

the presence of specific IgM antibodies to Leptospira.

¾ The test should be considered invalid if neither the

control band ‘C’ nor the test band ‘T’ appears. Repeat

the test with a new device.

Performance Characteristics

Leptocheck-WB was evaluated at the Royal Tropical

Institute, Amsterdam in parallel with other licensed tests

for the serodiagnosis of leptospirosis. The 47 sera evaluated

were from diverse serogroups of Leptospira.

Leptocheck-WB had a performance comparable to the

other tests.

Remarks

1. The intensity of the test line depends upon the stage of

the disease and the titres of the antibodies in the test

specimen.

2. As specific antibodies reach detectable levels about

one week after the onset of disease, a sample collected

very early may yield a negative test result.

3. If the test is negative and if leptospirosis is still

suspected, the test should be repeated with the second

sample collected at a later date in conjunction with

clinical reexamination.

4. In endemic areas, faint bands may appear occasionally

due to borderline IgM titres present as a result of

previous exposures.

5. It is recommended that the positive results obtained

must be reconfirmed using a confirmatory test such

as the MAT (microscopic agglutination test).

6. High titres of RF and heterophile antibodies may

interfere with the test; in such cases, the results must

be interpreted with caution.

7. The results must be correlated with clinical findings

to arrive at the diagnosis.

8. Do not use the test kit beyond expiration date.

Possible causes Solutions

1.  The flow properties of the nitrocellulose membrane are partially

affected leading to the movement of partially aggregated gold-sol

particles

Check the pouch for pinholes and also observe the desiccant for any

color change. The results of the test should be correlated with clinical

findings.

Troubleshooting

Problem: False positive results

Serology/Immunology 647

Possible causes Solutions

1. Hemolyzed blood samples were used for testing Do not use hemolyzed blood samples for testing

2. Reading taken after 15 minutes Read results exactly at 15 minutes

Possible causes Solutions

1. Whole blood samples having microclots or fibrin Ensure that the whole blood collected directly from fingerprick (without anticoagulant) should be free from microclots to avoid altered

flow and delayed reaction time

Problem: Faint Lines observed in control and test region

Problem: delayed results and altered flow

Problem: false negative results

Possible causes Solutions

1. Inadequate quantity of sample used for performing the test The exact number of drops of the sample as mentioned in the pack

insert should be dispensed for performing the test using the dropper

provided with the kit

2. The kit is exposed to very high temperatures leading to

deterioration of the antibodies coated on the device

Store at recommended temperature when not in use

3. Turbid or contaminated serum samples were used for testing Do not use turbid or contaminated serum samples for testing

4. Sample tested early after infection Specific antibodies reach detectable levels about one week after onset

of disease; hence,

 

 there is a possibility

of occurrence of false positives

Heterophile antibodies may be found in disease other than Infectious Mononucleosis.

Low titers have been detected in cytomegalic inclusion disease and Toxoplasmosis

5. Incorrect interpretation of results Ensure that the results are interpreted at 3 minute and as per instructions given in the

package insert. Positive and negative controls should be run with each series of tests

and results should be compared with these

Possible causes Solutions

1. Prozoning effect. In serum with very high titers, prozoning may be observed.

2. Hemolyzed samples may have been used. Avoid using hemolyzed samples for testing.

3. Reagents not brought to room temperature. Cold reagents could give false

negative results.

All reagents must be brought to room temperature before

use.

Troubleshooting

Immutex

Problem: False positive results

Problem: False negative results

Serology/Immunology 645

RAPID TEST FOR IGM ANTIBODIES TO

LEPTOSPIRA: LEPTOSPIROSIS

(LEPTOCHEK WB) (DEVICE)

(Courtesy: Tulip Group of Companies)

Introduction

Leptocheck-WB is a rapid, self-performing, qualitative,

sandwich immunoassay for the detection of Leptospira

specific IgM antibodies in human serum/plasma or

whole blood specimen. It is useful for the serodiagnosis of

current or recent leptospirosis. The broadly reactive genus

specific antigen employed in the test allows the detection

of Leptospira infections caused by a wide range of strains

of different serovars.

Summary

Leptospira are actively motile, delicate spirochetes

possessing a large number of closely wound spirals and

characteristic hooked ends. There are several species of

Leptospira and they may be saprophytic or parasitic. They

can be distinguished only under dark ground illumination

in the living state or by electron microscopy. Leptospirosis

is a zoonotic disease of worldwide prevalence. Humans

are infected when the water contaminated by the urine of

carrier animals enters the body through cuts or abrasions

on the skin or through intact mucosa of the mouth, nose

or conjunctiva. Clinical symptoms include fever, chills,

headache, conjunctivitis, myalgia and Gl-related symptoms,

kidney infection is a common sequelae.

Diagnosis may be made by demonstration of Leptospira

microscopically in blood or urine, by isolating them in culture

or by inoculation of guinea pigs, or by serological tests.

Leptocheck-WB, qualitatively detects the presence

of IgM class of Leptospira specific antibodies in human

serum/plasma or whole blood specimen.

Principle

Leptocheck-WB utilizes the principle of immuno -

chromatography, a unique two-site immunoassay on a

membrane. As the test sample flows through the membrane

assembly of the test device, the anti-human IgM-colloidal

gold conjugate forms a complex with IgM antibodies in the

sample. This complex moves further on the membrane to

the test window ‘T’ where it is immobilized by the broadly

reactive Leptospira genus specific antigens coated on the

membrane, leading to the formation of a red 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 antirabbit antibodies coated on the control window ‘C’ of the

membrane assembly, forming a red to deep purple colored

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

Reagents and Material Supplied

Each kit contains:

A. Individual pouches, each containing:

1. Test Device Membrane test assembly predispensed with Anti Human IgM-colloidal gold

conjugate, Leptospira genus specific antigens at

test window ‘T’ and anti-rabbit antiserum predispensed at the control window ‘C’.

2. Desiccant pouch

3. 5 µL sample loops.

B. Sample running buffer

C. Package insert.

Storage and Stability

The sealed pouches in the test kit and the kit components

may be stored between 4 and 30°C for the duration of the

shelf-life as indicated on the pouch.

Optional Material Required: 10 µL precision micropipettes.

Note

1. Forin vitro diagnostic use only. Notfor Medicinal Use.

2. Do not use beyond expiry date.

3. Read the instructions carefully before performing the

test.

 

Studies have cited the presence of heterophile antibodies

during the course of infection with infectious mononucleosis.

Reagent

Immutex is a ready-to-use, uniform suspension of

stabilized, specially treated horse erythrocytes highly

specific for heterophile antibodies associated with infectious

mononucleosis. The reagent does not react with normal

Forssman antibodies.

Each batch of reagent undergoes rigorous quality

control at various stages of manufacture for its specificity,

sensitivity and performance.

Reagent Storage and Stability

Store the reagents at 2 to 8°C. Do not freeze. The shelf-life

of the reagents is as per the expiry date mentioned on the

reagent vial labels.

Principle

Immutex is a rapid slide hemagglutination test for the

detection of heterophile antibodies. Immutex IM reagent

will agglutinate when mixed with serum containing

heterophile antibodies. No agglutination indicates

absence of heterophile antibodies.

Note

1. In vitro diagnostic reagent for laboratory and

professional use only. Not for medicinal use.

2. All the components derived from human source have

been tested for HBsAg and Anti-HIV antibodies and

found to be nonreactive. However, handle the material

as if infectious.

3. The reagents contain thimerosal 0.01% as preservative.

Avoid contact with skin or mucosa. On disposal, flush

with large quantities of water.

4. The reagent can be damaged due to microbial

contamination or on exposure to extreme temperatures.

It is recommended that the performance of reagents

should be verified with known positive and negative

controls provided with the kit.

5. Ensure resuspension of the stabilized erythrocyte

reagent before use to improve test readability by gently

inverting the vial.

6. Do not interchange vial droppers.

7. Only a clean and dry glass slide must be used. Clean

the slide with distilled water and wipe dry.

Sample Collection and Preparation

No special preparation of the patient is necessary prior to

specimen collection by approved techniques. Though fresh

serum is preferable, serum specimens stored at 2 to 8°C for

up to 24 hours, can also be used 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.

Materials Provided with the Kit

Reagent

Immutex IM reagent, Positive Control, Negative Control.

Accessories

Glass slide with six reaction circles, sample dispensing

pipettes, mixing sticks and rubber teats.

Additional Material Required

A high intensity direct light source, stopwatch.

Test Procedure

Bring all reagents and samples to room temperature before

use.

Qualitative Method

1. Gently mix the Immutex IM reagent to resuspend the

stabilized horse erythrocyte reagent.

2. Place one drop of the sample to be tested onto one of

the reaction circles of the glass slide using a sample

dispensing pipette provided with the kit.

3. Place one drop of the positive and negative control

onto separate reaction circles of the glass slide.

4. Add one drop of Immutex IM reagent to the test

644 Concise Book of Medical Laboratory Technology: Methods and Interpretations specimen on the slide. Do not let the dropper tip touch

the liquid on the slide.

5. Add one drop of Immutex IM reagent to each of the

controls.

6. Mix with separate mixing sticks, spreading the mixture

uniformly over the entire reaction circle.

7. Immediately start the stopwatch. Rock the slide gently,

back and forth, for 2 minutes.

8. Leave the slide undisturbed on the work table for a

further 1 minute.

9. Pick up the slide at the end of 1 minute and observe for

agglutination by rocking the slide gently back and forth.

Interpretation of Results

Agglutination is a positive test result and indicates

presence of heterophile antibodies in the test specimen.

No agglutination is a negative test result and indicates

absence of heterophile antibodies in the test specimen.

Remarks

1. Markedly lipemic, hemolyzed and contaminated

serum sample could produce nonspecific results.

2. Use of plasma rather than serum can lead to false

positive results.

3. Heterophile antibodies may be found in disease

other than infectious mononucleosis. Low titers have

been detected in cytomegalic inclusion disease and

toxoplasmosis.

4. Do not read the results beyond indicated testing time

limit.

5. As with all diagnostic tests, the result of the test should

be correlated with clinical findings to arrive at the final

diagnosis.

6. The reagent performance should be validated by

occasionally running the positive and negative

controls provided with the kit.

Possible causes Solutions

1. Plasma is used as a test specimen Only serum must be used for testing. Should a delay in testing occur, store samples

at 2–8°C

2. Markedly lipemic and contaminated serum

samples could produce non-specific results

Do not use lipemic and contaminated serum samples for testing

3. Drying of the reagent on slide Do not read results beyond 3 minutes. The test should not be carried out directly under

the fan

4. In other disease conditions,

 

 The nitrocellulose membrane has

lost its flow properties due to absorbance of moisture

Check the pouch for pinholes and also check the color of the desiccant (silica gel). A change in color form deep blue to white indicates

absorbance of moisture

2. The device is removed from the refrigerator and tested immediately leading to hydration of the sites on the nitrocellulose membrane

hence adversely affecting its flow properties

The test pouch should be brought to room temperature before being

tested

Serology/Immunology 643

TEST FOR INFECTIOUS MONONUCLEOSIS

(IMMUTEX)

(Courtesy: Tulip Group of Companies)

Summary

Infectious mononucleosis is a self-limited prolonged

illness strongly associated with Epstein-Barr Virus. Though

specific treatment is rarely required since the disease

is usually asymptomatic, potential complications, such

as inflammation of the liver, enlargement of the spleen,

pericarditis, myocarditis and encephalitis as well as

hemolytic anemia associated with this disease, require

physician’s attention.

In individuals with suppressed or abnormal

immunodeficiency disorders, cancer or those with recent

organ transplant, infectious mononucleosis occurs with

severe complications.

 

antibodies (IgM and IgG) to Dengue virus, if present in the

sample. This complex moves further on the membrane

to the test region where it is immobilized by the specific

human IgM antibody and/or human IgG antibody binding

proteins coated on the membrane leading to formation of a

colored band which confirms a positive test result. Absence

of these colored bands in the test window “T” indicates a

negative test result. A built-in control band in the control

window “C” appears when the test has been performed

correctly, regardless of the presence or absence of antiDengue virus antibodies in the specimen and serves to

validate the test performance.

Reagents and Materials Supplied

Each kit contains:

A. lndividual pouches, each containing:

1. Denguecheck-WB (Device) Membrane test assembly predispensed with recombinant Dengue

virus specific antigen colloidal gold conjugate,

streptavidin gold conjugate, anti-human IgM at

test region ‘M’ Protein A at the test region ‘G’ and

Biotin at the control region ‘C’.

2. Desiccant pouch

3. 5 µL sample loop.

B. Sample running buffer.

C. Package insert.

Storage and Stability

The sealed pouches in the test kit and the kit components

may be stored between 4 and 30°C for the duration of the

shelf-life as indicated on the pouch.

Optional Material Required: 5 µL precision micropipettes.

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 specimen as potentially infectious.

5. Follow standard biosafety guidelines for handling and

disposal of potentially infective material.

Specimen Collection and Preparation

1. No special preparation of the patient is necessary prior

to specimen collection by approved techniques.

2. Though fresh serum/plasma is preferable, specimen

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

delay in testing.

3. Whole blood samples collected with a suitable

anticoagulant such as EDTA or Heparin or Oxalate

can also be used.

4. Do not use turbid, lipemic, icteric and hemolyzed

specimen.

5. Repeated freezing, thawing of the specimen should be

avoided.

6. Specimen containing precipitates or particulate matter

must be centrifuged and the clear supernatant only

should be used for testing.

Testing Procedure and Interpretation of Results

1. Bring the kit components to room temperature before

testing.

2. Open the pouch and retrieve the test device. Once

opened, the device must be used immediately.

3. Label the test device with patient identity.

4. Add 5 µL of serum/plasma/whole blood, with the

micropipette into the sample port ‘A’, or using the

5 µL sample loop provided with the-kit, dip the loop

Serology/Immunology 641

into the sample and then blot into the sample port ‘A’.

Ensure that the loop does not retrieve clots or debris

from the sample.

5. Add five drops of sample running buffer in the reagent

port ‘B’.

6. Exactly at the end of 15 minutes, read the test results.

Interpretation of Results

Negative Test Result

The presence of only the single red/purple colored band

in the control window “C” indicates the absence of specific

antibodies against dengue virus or that the amount of

antibodies is below the detection limit of the test.

Positive Test Result

1. In addition to the band in the control window ‘C’,

appearance of two red/purple colored bands in the

test window at region ‘M’ and region ‘G’ indicates

the presence of Dengue virus specific IgM and IgG

antibodies (acute secondary infection).

2. In addition to the control band in the control window

‘C’, appearance of a red/purple colored band in the test

window at region ‘M’ indicates the presence of Dengue

virus specific IgM antibodies (acute primary infection).

3. In addition to the control band in the control window

‘C’, the appearance of a red/purple colored band in

the test window at region ‘G’ indicates the presence of

Dengue virus specific IgG antibodies (acute secondary

infection).

Invalid Result: If, after 15 minutes, no band is visible

either in the test or control window, the result is

considered invalid. The test should be repeated with a

new device.

Remarks

1. Do not use test kit beyond expiration date.

2. While sample should be collected as soon as possible

after onset of illness, it is recommended that followup of testing should be done on day 10 after the first

sample to allow seroconversion, especially when the

test is negative and Dengue virus infection is clinically

suspected.

3. Though Denguecheck-WB does provide evidence

to distinguish the past (secondary) infection from

current (primary) ongoing infection, a negative result

does not preclude the possibility of infection with

Dengue virus.

4. As with all diagnostic tests, a definitive clinical

diagnosis should not be based on the results of a single

test but should rather be made by a clinician after all

clinical findings have been evaluated.

5. The DHF is primarily the disease of children

under 15 years in hyperendemic areas. Impending

DSS symptoms include suspected abdominal

pain, persistent vomiting, change in the level of

consciousness, hypothermia and sudden decrease in

platelet counts.

6. Eighty percent of the patients may have detectable

levels of IgM antibody by day 5 of illness and 99% by

day 10.

7. IgM levels rise quickly and peak by two weeks

after onset of symptoms and then fall to become

undetectable over 2 to 3 months. IgG antibodies rise

quickly and peak at about two weeks postinfection and

then decline slowly over 3 to 6 months.

642 Concise Book of Medical Laboratory Technology: Methods and Interpretations Troubleshooting

Dengue Check WB and Leptocheck-WB

Problem: False positive results

Possible causes Solutions

1.  The flow properties of the nitrocellulose membrance are partially

affected leading to the movement of partially aggregated gold-sol

particles

Check the pouch for pinholes and also observe the desiccant for any

color change. The results of the test should be correlated with clinical

findings

Problem: Faint lines observed in control and test region

Possible causes Solutions

1. Hemolyzed blood samples were used for testing Do not use hemolyzed blood samples for testing

2. Reading taken after 15 min Read results exactly at 15 minutes

Problem: Delayed results and altered flow

Possible causes Solutions

1. Whole blood samples having microclots or fibrin Ensure that the whole blood collected directly from fingerprick (without anticoagulant) should be free from microclots to avoid altered

flow and delayed reaction time

Problem: False negative results

Possible causes Solutions

1. Inadequate quantity of sample used for performing the test The exact number of drops of the sample as mentioned in the pack

insert should be dispensed for performing the test using the dropper

provided with the kit

2. The kit is exposed to very high temperatures leading to deterioration of the antibodies coated on the device

Store at recommended temperature when not in use

3. Turbid or contaminated serum samples were used for testing Do not use turbid or contaminated serum samples for testing

4. Sample tested early after infection Specific antibodies reach detectable levels about one week after onset

of disease; hence follow-up testing after day 10 is recommended to

allow seroconversion

Problem: Invalid results

Possible causes Solutions

1. Pinholes/defect in the pouch.

 

6. Prozoning may sometimes be encountered in serum

containing very high titers on slide test.

7. Since techniques and standardization vary from

laboratory to laboratory a difference of titer corresponding to next or previous titer can be expected.

BRUCELLOSIS POSITIVE CONTROL

(Courtesy: Tulip Group of Companies)

Summary

Human brucellosis (diurnal, or undulant fever) is a

common febrile illness caused by infection with bacteria

of some of the Brucella species (abortus, melitensis). This

undulant fever is associated with symptoms, which are

often variable and nonspecific with chills, fever, sweats and

anorexia. On exposure, the body responds to this antigenic

stimulation by producing specific antibodies whose titers

rise slowly at early stages and then increases. Specific antibodies to the Brucella species are detectable a few weeks

after exposure and are of considerable importance in the

Serology/Immunology 639

diagnosis of Brucellosis. Information regarding the titer

of antibodies can be obtained by using specific Brucel

antigen suspensions.

The performance of the Brucel-A/Brucel-M antigen

suspensions can be validated with the help of Brucellosis

Positive Control.

Reagent

The Brucellosis Positive Control contains ready-to-use

standardized goat antiserum with polyspecific antibodies

having specific reactivity towards Brucella abortus and

Brucella melitensis antigens and is useful in the validation

of the performance of Brucel-A/Brucel-M reagents.

Reagent Storage and Stability

Store the reagent at 2 to 8°C. Do not freeze.

The shelf-life of the reagent is as per the expiry date

mentioned on the reagent bottle label.

Each batch of reagents undergoes rigorous quality

control at various stages of manufacture for its specificity,

sensitivity, and performance.

Principle

The Brucellosis Positive Control is mixed with the

Brucella antigen suspensions to be tested and allowed to

react. Specific reactivity of Brucella antigens if present in

the antigen suspensions will produce an agglutination

reaction. No agglutination indicates the deterioration of

the performance of the antigen suspensions.

Note

1. In vitrodiagnostic reagent for laboratory and professional

use only. Not for medicinal use.

2. The reagent contains thimerosal 0.01% as preservative.

Avoid contact with skin and mucosa. On disposal,

flush with large quantities of water.

Additional Material Required

Stopwatch, isotonic saline, glass slide with clear/white

background, appropriate pipettes/micropipettes, mixing

sticks and a high intensity direct light source.

Procedure

Bring all reagents to room temperature. Shake and mix the

Brucellosis Positive Control well before dispensing.

Slide Test Method

1. Place one drop of Brucellosis Positive Control onto the

reaction circle of glass slide.

2. Place 80 µL of saline onto the next reaction circle of

the glass slide.

3. Add one drop of test reagent (Brucella antigen

suspensions) in each of the above circles.

4. Mix contents of each circle uniformly over the entire

circle with separate mixing sticks.

5. Gently rock the slide back and forth, observe for

agglutination macroscopically at 1 minute against a

white background.

Interpretation of Results

Slide Test Method

Agglutination is a positive test result and indicates that the

Brucella antigen reagents are performing satisfactorily.

No agglutination is a negative test result and indicates the

deterioration of Brucella antigen reagents.

RAPID TEST FOR IgM AND IgG ANTIBODIES TO

DENGUE VIRUS: DENGUE FEVER

(DENGUECHECK-WB) (DEVICE)

(Courtesy: Tulip Group of Companies)

Introduction

Denguecheck-WB is a rapid immunochromatographic test

for the simultaneous detection of IgM and IgG antibodies

to Dengue virus in human serum/plasma/whole blood.

The test can be used as a screening test for Dengue viral

infection and as an aid for differential diagnosis of the selflimiting primary Dengue infections and the potentially

fatal secondary Dengue infections in conjunction with

other criteria.

Summary

Dengue fever virus (serotypes 1–4) belong to the family of

Flaviviridae, which is widely distributed in the epidemic

and endemic areas throughout tropical and subtropical

regions of the world. Dengue virus infection is considered

significant in terms of morbidity, mortality and economic cost

associated with it, an estimated 100 million cases of dengue

fever occurring throughout the world yearly. Dengue virus

is transmitted in nature principally by the day-biting Aedes

aegypti and Aedes albopictus mosquitoes. The mosquito

vector is highly domesticated and an urban species. Dengue

presents typically as a fever of sudden onset with headache,

retro-orbital pain, pain in the back and limbs (break-bone

fever), lymphadenopathy and maculopapular rash. Patients

diagnosed with dengue infection in endemic areas generally

have secondary infection, whereas patients in nonendemic

640 Concise Book of Medical Laboratory Technology: Methods and Interpretations areas are usually diagnosed with primary infection. Specific

antibody response to Dengue virus enables serodiagnosis

and differentiation between primary and secondary dengue

infections and detection of potentially life-threatening

conditions such as Dengue Hemorrhagic Fever (DHF) and

Dengue Shock Syndrome (DSS).

Denguecheck-WB is a new generation rapid

immunochromatographic test using highly specific and

purified immunodominant, Recombinant Dengue ‘Env.’

antigens. It is a simple test for the differential diagnosis of

Dengue virus infection.

Principle

Denguecheck-WB utilizes the principle of immunochromatography, a unique two-site, self-performing

immunoassay on a membrane. Specific human IgM and

human IgG antibody-binding proteins are immobilized on

the nitrocellulose membrane as two individual test bands

(IgM and IgG) in the test window “T” of the test device at

region “M” and region “G” respectively. The IgM band in

the test window “T” is closer to the sample well and the

IgG band is close to the control window “C”. As the test

sample flows through the membrane assembly within

the test device, the colored-Dengue specific recombinant

antigen-colloidal gold conjugate complexes with specific