This Dengue IgM and IgG Combo rapid test kit is a qualitative measure for detecting IgM and IgG antibodies of dengue virus present in human serum, plasma or whole blood. This test kit is only used for in-vitro diagnostic.
Dengue virus belongs to the Flavivirus group of viruses; it is one of the most significant mosquito-borne diseases in the world in terms of morbidity and mortality. It is transmitted principally through mosquito Aedes aegypti and Aedes albopictus type; there are four known serotypes of dengue. This virus can be found commonly throughout the tropic and subtropic regions of the world. Its symptoms include high fever, muscle pain, headache, and skin rash. The complications of this infection are dengue hemorrhagic fever or dengue shock syndrome. The immune response to this virus includes the production of IgM antibodies by the 5th day of infection that remains in the circulatory system for 30 to 60 days and IgG antibodies appear by the 14th day of symptom.
A secondary infection often results in high fever and, in many cases; it initiates hemorrhagic events and circulatory failure. In this infection, IgM antibody responds after 20 days and IgG antibodies rise within 1 to 2 days. So, patients with secondary infections have a positive IgG result with a positive IgM result as well. Thus, the use of a reliable and sensitive rapid serological test can detect the presence IgG and IgM antibodies are of great clinical utility. By using a mixture of highly purified dengue proteins, this test is able to detect all 4 Dengue serotypes.
Serum, plasma or the whole blood sample can be used with this test kit. When a specimen is added to the test, IgG and IgM antibodies in the specimen sample reacts with the gold particles coated with the dengue envelope proteins. As this specimen migrates along the length of the test, the anti-dengue IgG or IgM antibody particle complex is captured by the test band located in the test device window and cause a pale to the dark red band to form in the region. The intensity of the bands varies depending upon the amount of antibody present in the sample. The appearance of any color in the test region should be considered a positive result for IgG or IgM antibody. A red procedural control line should always develop in the test device window to confirm that the test has been performed properly.
All Specimens should be handled properly and treated as potentially infectious
Biological decontamination procedures should be followed for all the containers, equipment, surfaces, etc that come in contact with the specimens and all disposables should be disposed of as infectious waste.
For best results, strict adherence is required to these instructions. Be careful and do not touch the tip of the buffer bottle to the sample tube while adding a buffer to the tube. This will minimize the likelihood of contaminating the buffer reagent.
The buffer contains a low concentration of sodium azide as a preservative (less than 0.1 %), which is toxic. Do not mistakenly drink this buffer. High concentrations of sodium azide may react with the lead and copper in the plumbing to form explosive compounds. So, if disposing of down a drain, flush with an excess amount of water to minimize the accumulation of potentially explosive metal-azide compounds.
Do not use the test device or wash buffer beyond the stated expiration date marked on the package label.
Store the test kit and reagents according to the temperature range mentioned on the package label.
All test devices, buffer, and specimens should be kept at room temperature (2-30°C) before running the assay.
Do not re-use the test devices or buffer.
STORAGE AND SHELF LIFE OF REAGENTS
Store the test kit between 2° to 30°C and keep away from direct sunlight. Make sure to open only the number of devices that are going to be used. Once the test device pouch has been opened, it should be used immediately. The test kit may be used before the expiration date that is mentioned on the package label.
Wash your hands properly with soap and warm water. Choose a puncture site on the fingertip and clean it with alcohol. Squeeze the end of the fingertip and pierce it with the lancet, wipe away the first drop of blood with cotton. Then using provided pipette collect the blood from the puncture site.
Whole blood sample should be used immediately, if possible.
For serum test, centrifuge the whole blood to get a plasma or serum specimen.
If serum or plasma specimens cannot be tested immediately, then it should be refrigerated at 2 to 8°C. For storing greater than three (3) days, freeze the specimen at -20°C or below.
Dengue test device
Instruction for use
A complete set may also contain:
7 Alcohol pre pad
Remove the appropriate number of Dengue Combo Test Device pouches from the kit box.
Tear open the foil pouch and remove the device, lay the test device on a clean, flat work surface.
Add 1 drop (approximately 30ul) of whole blood or 2 to 3 drops of serum or plasma into the sample well with a pipet.
Then add 1to 2 drops (approximately 50-90ul) of wash buffer provided in the dropper bottle holding the bottle vertically from the sample well.
Negative results must be confirmed after 20 minutes, do not read the results after 30 minutes.
INTERPRETATION OF THE RESULTS
The control line and IgG line are visible on the test stripe, the test is positive for IgG antibodies.
This is indicative of past dengue infection.
The control line and the IgM lines are visible on the test strip, the test is positive for IgM antibodies.
This is indicative of primary dengue infection.
IgM and IgG Positive
The control lines, IgM and IgG are visible on the test strip, the test is positive for IgM and IgG antibodies.
This is indicative of secondary dengue infection.
Negative Test Result
The control line is the only line that is visible on the test device window means no IgG or IgM antibodies were detected, the result does not exclude dengue infection.
If symptoms persist, a new sample should be drawn from the patient in 3 to 5 days and then retested (see the limitations section).
Invalid Test Result
If the control line does not appear in the test device window, then the test results are INVALID regardless of the presence or absence of a line in the test region of the device window. Repeat the test using a new device.
Primary dengue is characterized by the presence of detectable IgM antibodies after 5 days of infection.
Secondary dengue is characterized by the elevation of specific IgM antibodies and the elevation of specific IgG antibodies. Usually, they will rise within 1 to 2 days after the onset of infection and IgM antibodies will be detectable after 20 days of infection. Therefore, depending on the sampling day, some secondary dengue infections may not be detected by IgM titer. A final diagnosis should be based on the test results in conjunction with other laboratory and clinical findings.
For the assay to be considered as valid the control line must appear and if it does not appear, the test results are not valid and must be repeated.
In addition to our laboratory’s standard quality control procedures, a positive and negative external control are tested at least once within each 25-test kits and by each operator perform testing within a kit. This verifies that the reagents and test devices are working properly and the operator is able to correctly perform the test procedure.
SENSITIVITY AND SPECIFICITY
A clinical study using a total 87 serum samples was conducted at various sites in 4 countries, the results of the Dengue IgG/IgM combo test were compared with a commercially available ELISA test.
The sensitivity and specificity of the IgG and IgM test results are given below:
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One Step Dengue Test (+)
One Step Dengue Test (- )
Sensitivity: 97% Specificity: 96%
98% accuracy based on the Internal Quality Control Standards.
This Dengue IgG/IgM combo test has been found to be stable for up to 24 months from the date of manufacturing when stored between 4 to 30° C. The expiry date of each test can be found on the box. No component or reagent should be used beyond its printed expiration date.
LIMITATIONS OF THE TEST
This test detects the presence of antibodies to dengue in the specimen and should not be used as the sole criterion for the diagnosis of a dengue viral infection. Serological cross-reactivity with other flaviviruses is common ex- West Nile, Japanese encephalitis, yellow fever, etc; therefore it is possible that patients with these viruses may show some level of reactivity with this test.
As with all the diagnostic tests, the result must be correlated with clinical findings. If the test result is negative and a dengue infection symptom still exists, it is recommended to do follow-up test using other clinical methods.
A negative serological result at any time does not preclude the possibility of early infection of Dengue virus.
The use of lipemic or icteric samples should be avoided.
Strict adherence to the test procedure is required; do not re-use the negative test devices and do not adulterate the wash solution reagent.
This test kit cannot be used to monitor the therapy or to estimate the relative antibody titer.
The test should not be used on the specimens from immunosuppressed individuals.
A final diagnosis should be based on these test results in conjunction with other clinical and laboratory findings.