|Storage:||2-30℃||Shelf Time:||24 Months|
diagnostic tests for infection,
infectious disease diagnostic tests
The EBNA IgG Rapid Test Cassette (Whole Blood/Serum/Plasma) is a rapid chromatographic immunoassay for the qualitative detection of IgG antibodies to EBNA of Epstein-Barr virus in human whole blood, serum, or plasma.
Epstein-Barr Virus (EBV) is a ubiquitous human virus which causes infectious mononucleosis (IM), a self- limiting lymphoproliferative disease 1 . By adulthood virtually everyone has been infected with and has developed immunity to the virus. In underdeveloped countries, seroconversion to the virus takes place in early childhood and is usually asymptomatic 2 . In more affluent countries, primary EBV infections are often delayed until adolescence or later, and manifest as IM in about 50% of this age group 3-5 . Following seroconversion, whether symptomatic or not, EBV establishes a chronic, latent infection in B lymphocytes which probably lasts for life 6 . EBV replicates in oropharyngeal epithelial cells and is present in the saliva of most patients with IM 7 . In addition, 10-20% of healthy persons who are EBV antibody positive shed the virus in their oral secretions 6-8 . Reactivation of the latent viral carrier state, as evidenced by increased rates of virus shedding, is enhanced by immunosuppression, pregnancy, malnutrition, or disease 8,9 . Chronic EBV infections, whether latent or active, are rarely associated with disease. However, EBV has been implicated at least as a contributing factor in the etiology of nasopharyngeal carcinoma, Burkitt’s lymphoma, and lymphomas in immunodeficient patients 4,8 . The Paul-Bunnell-Davidsohn test for heterophile antibody is highly specific for IM 10 . However, 10-15% of adults and higher percentages of children and infants with primary EBV infections do not develop heterophile antibodies 11 . There is a need for EBV-specific serological tests to differentiate primary EBV infections that are heterophile negative, from mononucleosis-like illnesses caused by other agents such as cytomegalovirus, adenovirus, and Toxoplasma gondii 4 . Antibody titers to specific EBV antigens correlate with different stages of IM 4,10-12 . Both IgM and IgG antibodies to the viral capsid antigen (VCA) peak three to four weeks after primary EBV infection. IgM anti-VCA antibodies decline rapidly and are usually undetectable after 12 weeks. IgG anti-VCA antibody titers decline slowly after peaking but last indefinitely. Antibodies to EBV nuclear antigen (EBNA) develop from one month to six months after infection and, like anti-VCA antibodies, persist indefinitely 11,12 . Antibodies to EBNA indicate that the infection was not recent. 11 EBV early antigens (EA) consist of two components; diffuse (D), and restricted (R). The terms D and R reflect the different patterns of immunofluorescent staining exhibited by the two components 13,14 . Antibodies to EA appear transiently for up to three months during the acute phase of IM in 85% of patients 15,16 . The antibody response to EA in IM patients is usually to the D component, whereas silent seroconversion to EBV in children produces antibodies to the R component 5,11 . A definitive diagnosis of primary EBV infection can be made with 95% of acute phase sera based on the detection of antibodies to VCA, EBNA, and EA. 12
The EBNA IgG Rapid Test Cassette (Whole Blood/Serum/Plasma) is a rapid test that utilizes a combination of EBV nuclear antigen coated colored particles for the detection of NA IgG antibody to Epstein-Barr virus in human whole blood, serum, or plasma.
How to use?
Allow the test cassette, specimen, buffer and/or controls to reach room temperature (15-30°C) prior to testing.
1. Bring the pouch to room temperature before opening it. Remove the test cassette from the sealed pouch and use it within 1 hour.
2. Place the cassette on a clean and level surface.
To use a dropper: Hold the dropper vertically, draw the specimen about 1cm above the upper end of the nozzle as shown in illustration blew, transfer 1 drop of the serum/plasma (approximately 10μl) or 2 drops of the whole blood (approximately 20μl) to the specimen well (S) of the test cassette, then add 2 drops of buffer (approximately 80μl) and start the timer.
To use a micropipette: Pipette and dispense 10μl of serum/plasma or 20μl of whole blood to the specimen well (S) of the test cassette, then add 2 drops of buffer (approximately 80μl) and start the timer.
3. Wait for the colored line(s) to appear. Read result at 15 minutes. Do not interpret the result after 20 minutes.
Note: It is suggested not to use the buffer beyond 6 months after opening the vial.
INTERPRETATION OF RESULTS
(Please refer to the illustration above)
POSITIVE: * Two distinct colored lines appear. One colored line should be in the control region (C) and another colored line should be in the test region (T).
*NOTE: The intensity of the color in the test line region (T) will vary depending on the concentration of EBNA IgG present in the specimen. Therefore, any shade of color in the test region should be considered positive.
NEGATIVE: One colored line appears in the control region (C). No apparent colored line appears in the test region (T).
INVALID: Control line fails to appear. Insufficient specimen volume or incorrect procedural techniques are the most likely reasons for control line failure. Review the procedure and repeat the test with a new test cassette. If the problem persists, discontinue using the test kit immediately and contact your local distributor.