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OXOID INFECTIOUS MONONUCLEOSIS KIT

Code:  DR0780

A two minute latex agglutination test for the specific detection of infectious mononucleosis heterophile antibody, for qualitative and semi-quantitative procedures, to aid in the diagnosis of infectious mononucleosis.

Introduction
Infectious mononucleosis (glandular fever) is an acute infectious disease caused by the Epstein-Barr virus and primarily affects lymphoid tissue. It is characterised by the appearance of enlarged and often tender lymph nodes, enlarged spleen, and abnormal lymphocytes in blood. Patients usually, but not always, develop a transient heterophile antibody response. The IM heterophile antibodies appear, especially during acute illness, in about 80 to 90% of adolescents and young adults with classical IM¹. The IM antibody is detected in a smaller number of young children with the classical disease. Since the majority of young children do not develop the full-scale syndrome in the course of primary infection, they should, in general, not be expected to develop IM heterophile antibodies. The IM antibody titre usually achieves significant diagnostic levels by the end of the first week of illness. In this regard, it behaves much like IgM specific Epstein-Barr Virus (the etiological agent for IM) antibodies^2,3 IM antibodies can persist for some period of time or reappear many years later^4,5.

The first report that described the presence of heterophile antibodies in patient sera with infectious mononucleosis was by Paul and Bunnell⁶. They described a method using sheep red cells as particles for agglutination. Due to the presence of other antigens on the sheep red cell, it became necessary to absorb "heterophile" antibody-containing specimens with substances from animal organs to remove non-IM agglutinins for sheep or horse red cells⁷. In this fashion, the absorbed serum specimens which retained agglutination capability were considered specific for the IM heterophile antibody. Alternatively, when boiled bovine red cells were used for absorption, they would selectively remove only the IM heterophile antibody. As a result, the specificity of the original agglutination observation was confirmed since this process would remove only the IM heterophile antibody. In contrast, when boiled bovine red cells were used to detect the IM heterophile antibody, there was no need to perform a differential absorption step. Bovine red cells do not contain antigens that react with non-IM agglutinins⁸. Furthermore, it has been demonstrated that the antigen from bovine red cells exhibits greater potency to specifically inhibit IM agglutination than antigen from either horse or sheep red cells⁹. Thus, when horse or sheep red cells are used in an IM antibody detecting-test system, specificity of a positive result must always be confirmed. This is due to the presumptive nature of the test when horse or sheep red cells are used as the particles to detect IM antibody.

Principle
Latex particles used in the Oxoid Infectious Mononucleosis Kit are sensitized with a bovine red cell-mononucleosis antigen. Due to the use of a bovine source, there is no need to perform differential absorptions to verify the specificity of the test results. When agglutination is observed, a diagnosis of IM is highly probable. The presence of infectious mononucleosis antibody in serum or plasma at detectable levels will interact with the sensitized particles to produce visible aggregation, which is a positive result.

Components of the kit
DR0781M Test Latex
Latex particles sensitized with bovine red cell membrane substance suspended in buffer. Each kit contains sufficient reagent for 100 tests
DR0782M Positive Control
Human serum containing specific mononucleosis heterophile antibody, diluted in buffer. Each kit contains sufficient reagent for 25 tests
DR0783M Negative Control
Normal human serum diluted in buffer. Each kit contains sufficient reagent for 25 tests
Disposable black slides
Paddle Pastettes
To deliver and mix specimens - 50µl
Instructions for Use (IFU)

Materials required but not provided
Clinical rotator capable of 100 rpm
High intensity lamp
Graduated pipettes or micropipettors for serial dilution
0.85% Saline for diluting specimens
12 x 75 mm Tubes
Timing device
Plastic mixing sticks

Storage
Store reagents at 2-8°C. Do not freeze. Under these conditions the reagents will retain their activity until the date shown on the bottle. Do not dilute the latex or control reagents or interchange them with other Oxoid Infectious Mononucleosis Kit lot numbers.

Precautions
This product is for in vitro diagnostic use and should be used by properly trained individuals. Precautions should be taken against the dangers of microbiological hazards by properly sterilising specimens and containers after use. Directions should be read and followed carefully. Contains 0.1% sodium azide as a preservative.

Specimen collection, storage and transport
Serum or plasma is the only acceptable sample to be used for testing with the Oxoid Infectious Mononucleosis Kit. Serum should be removed from centrifuged, fully clotted whole blood and transferred to a clean, labelled tube. If plasma is needed for other tests, use heparin, EDTA, or CPDA-1 as the anticoagulant during whole blood collection. The resulting plasma should be transferred from the centrifuged blood tube to a clean, labelled tube. It is preferable to test samples on the day of collection.

If testing is not performed on the day of collection, store the serum or plasma in a sealed, labelled tube at 2-8°C for up to one week. A preservative, such as sodium azide (0.1%) or thiomersal (0.1%), may be added (final concentrations). If longer periods of storage are used, sample(s) should be frozen at or below -20°C. Avoid repeated freeze-thaw cycles of specimen(s).

Serum or plasma can be heated for 30 minutes at 56°C if desired. Clarify the heated specimen before testing by centrifugation. It is good practice to centrifuge specimens which have been stored before testing.

Specimens that are grossly haemolysed, contain floating material or sediment, are turbid, or are inadequate in volume should not be used. This may occur as the result of improper handling or bacterial contamination, which may cause protein denaturation.  A fresh specimen should be obtained.

Limitions of the procedure
The Oxoid Infectious Mononucleosis Kit must be part of other clinical and diagnostic results. Other disease states can mimic IM and must be differentiated from it¹⁰. The laboratory results must be reviewed in light of the patient history by a physician.

References
1. Sumaya, C. V. 1986. Lab. Manag. 24:37-46.
2. Henle, 0., W. Henle, and V. Diehl. 1968. Proc. Natl- Acad. Sci. USA. 59:94-101.
3. Specter, S.A_. and V. Michelotti. 1985. September:65-80.
4. Askinazi, C., F.S. Cole, and J. L. Brusch. 1976. JAMA 236:1492-1493.
5. Hoagland. R.J. 1963. New Engl. J. Med. 269:1307-1308.
6. Paul, J.R. and W.W. Bunnell. 1932. Am. J. Med. Sci, 183:90-103.
7. Davidsohn, I. 1937. JAMA. 108:289-295.
8. Bailey, G.H, and S. Raffel. 1935. J. Clin. Invest. 14:228-244.
9. Fletcher, MA. and B J. Woolfolk. 1971. J. Immunol. 107:842-853.
10. Beshner, R.L and S.E. Shuler. 1967. Clin. Pediatr. 6:393-399.