Manual of basic techniques for a health laboratory - libdoc.who.int

190 Manual of basic techniques for a health laboratoryFig. 4.156 Applying antigen to the test cardFig. 4.157 Preparation of controls for the CATT3. Using the second card, test the collected blood. Place one drop of blood fromthe first microhaematocrit tube in well 1, from the second tube in well 2, etc.(Fig. 4.158). Discard the microhaematocrit tube in a jar containing water withdetergent.4. Using a stirring rod, mix the reagents in each well of the first card and the reagentsand blood samples in each well of the second card. Spread the mixture sothat it covers the well (Fig. 4.159). Use a separate stirring rod for each well orclean the rod with a piece of tissue paper or a cloth between each well to avoidcontamination of the samples.5. Place both cards on the rotator, cover and set the timer to 5 minutes. If it is amanual rotator, check the time with your watch. The rotation speed should beslow, approximately 100g. If the rotation speed is too fast, clumps will settle atthe edge of the wells; if it is too slow, the reaction will be weak.6. After 5 minutes, examine the plates and record the reactions in each well. Donot allow the samples to dry out. If any samples have dried out, the test shouldbe repeated.