The use of automated complement fixation techniques in the Brucellosis Eradication Scheme

Abstract

Automation of the complement fixation test for diagnosing Brucella abortus infection in cattle has allowed this difficult, time-consuming and labour-intensive hut most specific test to he used for large scale serodiagnosis in New Zealand's Brucellosis Eradication Scheme. The automated test has the advantages of eliminating much human error, of improving accuracy and of reducing the costs of labour and reagents.

The Auto-Analyzer performs a warm complement fixation test at a single serum dilution. Each batch of 39 serum samples is compared with a standard positive control serum with a complement fixing antibody activity equivalent to 1/30 of the second International Standard Ani-Brucella abortus Serum. All sera with an antibody level equal to, or greater than, the standard serum are regarded as positive to the test. A titre for serum tested by the automated method is not obtained, and positive sera that prozone strongly may be recorded as negative. Where necessary, the semi-automated microtitre complement fixation test is used to delineate titres and the status of doubtful automated CFT results. The automated and microtitre complement fixation tests use the same reagents; only relative concentrations differ.