A comparison between the haemagglutination inhibition and complement fixation tests for Newcastle disease

The value of the complement fixation (CF) test as a means of assessing the immune response of fowls to Newcastle disease virus was examined using several strains of virus. A close degree of correlation was found between the CF test and the simpler haemagglutination-inhibition (HI) test. Like the HI test, the CF test only gave an indication of the immune status and was not a direct measurement of immunity.