Use of an image analyser for rubella radical haemolysis plates

A method is described for the reading of rubella radial haemolysis plates using an image analyser. A quantitative assessment of rubella antibody is made by measuring the area of zones of haemolysis displayed on a video screen. When linked to a microcomputer, this reduces the time taken for the reading and reporting stages of testing. The majority (97.9%) of sera could be assessed by this method; problems relating to the remainder are discussed.