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

4. Parasitology 191Fig. 4.158 Applying test samples to the test cardFig. 4.159 Mixing the samples in each well of the test cardFig. 4.160 Strong positive reaction inthe CATTFig. 4.161 Weak positive reaction inthe CATTResultsStrongly positive reactions (Fig. 4.160)Small or large clumps of particles are visible over the whole well or form a circlearound the edge of the well.Weak positive reactions (Fig. 4.161)Very small clumps of particles are spread throughout the well or form a circle aroundthe edge of the well. Repeat the test using serum or plasma.