The complement fixation test in tuberculosis has become so well known through a number of recent articles on the subject, and the literature has so often been reviewed that a detailed discussion of previous work is unnecessary. All workers have not been able to secure good results with the test and there has been some lack of conformity between the results of the fixation tests and the clinical diagnoses It may be mentioned, however, that although different preparations of antigen have been used those investigators whose interest in the reaction has led to a considerable experience in performing the tests have obtained the best and most consistent results. The skepticism that exists in some localities regarding the value of the reaction depends to a certain extent on a lack of understanding of the difficulties in securing a close agreement between the fixation tests and the clinical examination.
Probably several factors
COOKE JV. COMPLEMENT FIXATION FOR TUBERCULOSIS IN CHILDREN. Am J Dis Child. 1921;21(1):78-88. doi:10.1001/archpedi.1921.01910310083007