This test is done to determine if an already isolated and identified Corynebacterium diphtheriae produces toxins.The plate comprises molten agar, rabbit serum (for enrichment) and potassium tellurite. Place a filter paper strip impregnated with antitoxin across the middle of the plate. Allow the filter paper to sink to the bottom of the plate. Let the plate solidify and ensure that it is dry before use.
All inoculations are done at right angles to the long edge of the filter paper. All inoculations are done parallel to each other. Finally ensure that the test organism is next to the positive control. The inoculations are line streaks.
After incubation (18-24 hours at 37 degrees) examine the plate for white lines of precipitation that extend outwards from the line of inoculation/bacterial growth at an angle of 45 degrees. If you inoculated the test next to the positive control, and if the test is positive, you will see a wave like formation.
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