Intensity of test line relates to amount of target Ab deposited.

<p>Dilution series of four highly positive sera samples indicate that the intensity of the purple color at the test line decreases when a lower amount of target Ab is deposited on the strip. The sample appears negative when a dilution of 1/50 is used. A: undiluted sample; B: 1/10 sample dilution; C: 1/20 sample dilution; D: 1/30 sample dilution; E: 1/40 sample dilution; F: 1/50 sample dilution.