One-Step Dengue IgG/IgM Rapid Test Cassette

One-Step Dengue IgG/IgM Rapid Test

Dengue IgG/IgM INTENDED USE

THE ONE STEP ANTI-DENGUE (IGM & IGG) TRI-LINE TEST IS A COLLOIDAL GOLD ENHANCED, RAPID IMMUNOCHROMATOGRAPHIC ASSAY FOR THE QUALITATIVE DETECTION OF ANTIBODIES (IGM & IGG) TO DENGUE VIRUS (DV) IN HUMAN  WHOLE BLOOD, SERUM OR PLASMA. THIS TEST IS A SCREENING TEST, AND ALL POSITIVES MUST BE CONFIRMED USING AN ALTERNATE TEST SUCH AS WESTERN BLOT. THE TEST IS INTENDED FOR HEALTHCARE PROFESSIONAL USE ONLY.

Dengue IgG/IgM SUMMARY

Dengue viruses (DVs) are the causative agent of dengue fever, dengue hemorrhagic fever and dengue shock syndrome. It is estimated that at least 80 million DV infections occur worldwide annually. The majority of DV infections are asymptomatic. In symptomatic DV infection, clinical syndromes range from an undifferentiated febrile illness to dengue fever (DF) to dengue hemorrhagic fever (DHF), a plasma leakage syndrome that, in its most severe form dengue shock syndrome (DSS) can be life threatening.

PRINCIPLE OF THE PROCEDURE

The assay starts with a sample applied to the sample well.  A recombinant DV antigen conjugated to colloidal gold embedded in the sample pad reacts with the DV antibody present in blood, serum or plasma forming conjugate-DV antibody complex.  As the mixture is allowed to migrate along the test strip, the conjugate-DV antibody complex is captured by mouse anti human IgM-µ chain (T1) or mouse anti human IgG(T2)  immobilized on a membrane forming a colored test line in the test region.  A negative sample does not produce a test line due to the absence of colloidal gold conjugate-DV antibody complex.  The antigens used in the conjugate test are recombinant proteins that correspond to highly immunoreactive regions of DV.  A colored control line in the control region appears at the end of test procedure regardless of test result. This control line is the result of colloidal gold conjugate binding to the anti-DV antibody immobilized on the membrane. The control line indicates that the colloidal gold conjugate is functional.

Two test lines are coated on the membrane; on T1 region mouse anti human IgM-µ chain is immobilized; On T2 region a mouse anti human IgG is coated, a positive result appearing on T1 region indicates a DV IgM positive samples and a positive result appearing on T2 region indicates a DV IgG positive samples.

REAGENTS AND MATERIALS SUPPLIED

*Test cards/ test strips individually foil pouched with a desiccant

*Sample diluent

*Package Insert

MATERIALS REQUIRED BUT NOT PROVIDED

*Pipettes to transfer specimen.

*Positive and negative controls

STORAGE AND STABILITY

1.Store unused kit at 2 - 30°C.

2.Store test cards/strips at 2 - 30°C and away from direct sunlight.

WARNINGS AND PRECAUTIONS

All positive results must be confirmed by an alternate method.

1.Treat all specimens as though potentially infectious. Wear gloves and protective clothing when handling specimens.

2.Devices used for testing should be autoclaved before disposal.

3.Do not use kit materials beyond their expiration dates.

4.Do not interchange reagents from one kit lot to another.

SAMPLE COLLECTION AND STORAGE

Whole Blood:

1.Collect whole blood specimens following regular clinical laboratory procedures.

2.Heparinized capillary tubes treated with anticoagulant must be used for collecting blood samples.

3.Whole blood specimens should be used immediately after collection.

Serum or Plasma:

1.Collect serum or plasma specimens following regular clinical laboratory procedures.

2.Storage: A specimen should be refrigerated if not used the same day of collection. Specimens should be frozen if not used within 3 days of collecting. 0.1% of sodium azide can be added to specimen as preservative without affecting the results of the assay.

ASSAY PROCEDURE

Do not open pouch until you are ready to test the sample.

1.Bring all reagents and specimens to room temperature.

2.Remove the test card from the foil pouch and place on a clean dry surface.

3.Identify the test card for each specimen or control.

4.Dispense one drop (1ml) of the specimen or control into the ”S” well on the card, then add two drops of sample diluent into the”D” well.

5. Interpret test results at 15 minutes.

Caution: Use a clean pipette or tip for every sample to avoid cross-contamination.

NOTE: A positive result may be interpreted early, however read any negative at 15 minutes to ensure sample is negative and not a low concentration of the anti-DV antibody. Do not interpret the result after 20 minutes.

It is recommended to run a known positive control and negative control in each performance to ensure the assay procedure.

READING THE TEST RESULTS

1.Positive: Control line and at least one test line appear on the membrane. The appearing of T1 test line indicates a DV  IgM positive result, the appearing of T2 test line indicates a DV IgG positive result, the appearing of both T1 and T2 test lines indicate both DV IgM & IgG positive result. The lower the antibody concentration is, the weaker the test line is.

2.Negative: Only the control line appears on the membrane. The absence of a test line indicates a negative result.

3.Invalid: There should always be a control line in the control region regardless of test result.  If control line is not seen, the test is considered invalid. Repeat the test using a new test device.

Note: It is normal to have a slightly lightened control line with very strong positive samples as long as it is distinctly visible.

PERFORMANCE CHARACTERISTICS

1.Specificity

In an in-house laboratory study, 63 confirmed negative samples were evaluated with Advanced Quality One Step Anti-Dengue (IgM & IgG) Tri-line Test using EIA and Western Blot as reference tests. The study gave 100% specificity for the

test. 

2.Sensitivity

  In the above-mentioned study, Advanced Quality One Step Anti-Dengue (IgM & IgG) Tri-Line Test was evaluated with 32 confirmed positive samples. The sensitivity of Advanced Quality One Step Anti-Dengue (IgM & IgG) Tri-line Test was found to be 100% relative to consensus with EIA results, supported by Western Blot assay.

WARNING

1.Only samples that are not hemolyzed and that are with good fluidity can be used in this test.

2.Fresh samples are best but refrigerated and frozen samples can be used. 

3.Do not agitate the sample.  Insert a pipette just below the surface of the sample to collect the specimen.

LIMITATIONS OF THE TEST

Although a positive result may indicate infection with dengue virus, a diagnosis of DV can only be made on clinical grounds, if an individual meets the case definition for DV established by the Centers for Disease Control. For samples repeatedly tested positive, more specific supplemental tests must be performed. Immunochromatographic testing alone cannot be used to diagnose DV even if the antibodies against DV are present in a patient specimen. A negative result at any time does not preclude the possibility of DV infection.

Rebecca Yan