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SG Diagnostics

SG Diagnostics Dengue IgG/IgM & Ns1 Combo Rapid Test Kit

SG Diagnostics Dengue IgG/IgM & NS1 Combo Rapid Test Kit is a rapid, visual, qualitative and convenient immunochromatographic in vitro assay for the differential detection of dengue IgG/IgM antibody and NS1 antigen of dengue virus serotypes 1 – 4 in whole blood, serum or plasma samples. The test is intended for professional use in the diagnosis of dengue virus infections.

Dengue NS1 antigen is a highly-conserved glycoprotein that is present at high concentrations in the sera of dengue-infected patients during the early clinical phase of the disease. NS1 antigen is found from the first day and up to 9 days after onset of fever in blood samples of primary or secondary dengue infected patients.

Serological studies have shown that during primary infections, dengue-specific IgM antibodies are found by the 5th day of infection and remain in circulation for 30-60 days, while IgG antibodies appear by the 14th day of infection and persist for life. In contrast, during secondary dengue virus infection, specific IgG and IgM levels significantly increase at 1 – 2 days and the 20th day after infection, respectively. Thus, different profiles of humoral immune responses in primary and secondary dengue viral infections can be used for differential diagnosis. This is of clinical significance in predicting progression and prognosis of the disease. The presence of high titers of IgG antibodies does not interfere with the detection of IgM antibodies in the sample.

 

The dengue NS1 portion of this test is an antigen-capturing immunochromatographic assay, which detects the presence of dengue NS1 antigen in human blood samples. Monoclonal antibodies specifically against NS1 antigen are 1) conjugated with colloidal gold and deposited on the conjugate pad, and 2) immobilized on the test line of the nitrocellulose membrane. When a blood sample is added the antibody conjugate is rehydrated and the NS1 antigens, if any in the samples, will interact with the colloidal gold conjugated antibodies. The antigen-antibody-gold complex will migrate towards the test window until the Test Zone (NS1) where they will be captured by immobilized antibodies, forming a visible red line (Test band), indicating a positive result. If dengue NS1 antigen are absent in the sample, no red line will appear in the Test Zone (NS1), indicating a negative result.

The principle of the dengue IgG/IgM portion of this test is an antibody-capture immunochromatographic assay for the simultaneous detection and differentiation of IgG & IgM antibodies to dengue virus in human blood samples. Dengue virus-specific antigens are conjugated to a colloidal gold and deposited on the conjugate pad. A unique combination of anti-human IgG & IgM antibodies are immobilized on the test zone of the nitrocellulose membrane, as two individual test lines (IgG line and IgM line) in the test window of the test device. The IgG line in the test window is closer to the sample well and followed by IgM line. When the sample is added the gold-antigen conjugate is rehydrated and the dengue IgG and/or IgM antibodies, if any in the sample, will interact with the gold conjugated antigen. The antigen-antibody-gold complex will migrate towards the test window until the test zone where it will be captured by the relevant anti human IgG and/or anti-human IgM, forming a visible pink line, indicating a positive result. If dengue antibodies are absent in the sample, no pink line will appear in the Test Zone, indicating a negative result.

To serve as an internal process control, a control line should always appear at the Control Zone (C) of both test windows after the test is completed.

  • The assay time is shorter (within 10 minutes as compared to around 24 hours for enzyme-linked immunosorbent assay (ELISA))
  • The cost is cheaper than ELISA
  • The test can be carried out at the point-of-care
  • It is a one-step assay that requires no special skills or instrumentation to achieve the result(s)
  • It has a long shelf life and assay reagents do not require refrigeration or freezer storage
  • The samples do not need to be pre-treated before applying to the assay
  1. Remove the testing device from the sealed pouch by tearing at the notch and place the testing device on a leveled surface.


  2. Add samples (Whole blood or Serum/Plasma) 
  3. Dengue IgG/IgM: Add samples with pipette to the upper area (close to the test window) of the sample well of the test device according to the following table. Hold the pipette vertically and gently touch the end against the pad within the sample well for transferring). 
  4. Dengue NS1: Hold the sample dropper vertically. Add the specimen without air bubbles into the Sample Well according to the following table.



  5. Add diluents : Immediately add 2 drops (90 μl) of diluents to the proper sample well of the testing device according to following table:

  6. Read the results in 10-30 minutes. Read results as shown under interpretation of results. 
  7. Note: Strong positive specimens may produce positive results in as little as 1 minute and confirm negative results in 20-30 minutes. DO NOT INTERPRET RESULTS AFTER 40 MINUTES.

NS1 Results

Negative
A pink colored band appears only at the control region (C), indicating a negative result for Dengue virus infection. 

Positive 
A clear pink control band (C) and a detectable test band (NS1) appears, indicating a positive result for Dengue virus infections. 

Invalid 
No visible band appears at the control region (C). Repeat with a new test device. If the test still fails, please contact the distributor with the lot number.

Negative 
A pink colored band appears only at the control region (C), indicating a negative result for Dengue infection. 

Positive 
Pink colored bands appear at the control region (C) and IgM and /or IgG region. 

  1. IgG and IgM Positive, visible bands indicating positive result for a possible late primary or acute secondary infection. 
  2. IgM positive, a visible band at IgM region, indicating positive result for a possible primary dengue infection. 
  3. IgG positive, a visible band at IgG region, indicating a positive result for a possible secondary infection or past infection. 

Invalid 
No visible band appears at the control region (C). Repeat with a new test device. If the test still fails, please contact the distributor with the lot number

Coming soon

  • World Health Organization (WHO). URL: https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue. Accessed on 1st February 2021.
  • Luo, Robert, Noah Fongwen, Cassandra Kelly-Cirino, Eva Harris, Annelies Wilder-Smith, and R. W. Peeling. “Rapid diagnostic tests for determining dengue serostatus: a systematic review and key informant interviews.” Clinical Microbiology and Infection 25, no. 6 (2019): 659-666.
  • Raafat, Nader, Stuart D. Blacksell, and Richard J. Maude. “A review of dengue diagnostics and implications for surveillance and control.” Transactions of The Royal Society of Tropical Medicine and Hygiene 113, no. 11 (2019): 653-660.

Coming soon

Test Kit Specifications Materials Provided

Test Cassettes (20)
A test cassette consists of test strip, packed individually in sealed desiccant foil pouch with a sample dropper.
Diluent I (20)
3mL
Diluent II (20)
3mL
Product Insert (1)

Test Kit Characteristics

Assay format
Lateral flow test / immunochromatographic
Instrument
No
Testing Time
10 -30 mins
Specificity
IgG/IgM 94.89%
NS1 93.72%
Sensitivity
IgG: 92.78%
IgM: 89.32%
NS1: 93.97%
Type of analyte
NS1 antigen, anti-Dengue IgG and IgM antibodies
Sample material
Whole blood, serum or plasma

External Clinical Evaluation

For more information, you can download the file below.