Manual complement-fixation test.
Manual complement-fixation (CF) test. A test to determine the brucellosis disease status of test-eligible cattle and bison when conducted according to instructions approved by APHIS and the State in which the test is to be conducted. Cattle and bison are classified according to the following reactions:
(i) Cattle and bison which are not official vaccinates:
(A) Fifty percent fixation (2 plus) in a dilution of 1:20 or higher—brucellosis reactor;
(B) Fifty percent fixation (2 plus) in a dilution of 1:10 but less than 50 percent fixation (2 plus) in a dilution of 1:20—brucellosis suspect;
(C) Less than 50 percent fixation (2 plus) in a dilution of 1:10—brucellosis negative;
(ii) Official vaccinates vaccinated with a Brucella abortus Strain 19 approved brucella vaccine:
(A) Twenty-five percent fixation (1 plus) in a dilution of 1:40 or higher—brucellosis reactor;
(B) Fifty percent fixation (2 plus) in a dilution of 1:10 but less than 25 percent fixation (1 plus) in a dilution of 1:40—brucellosis suspect;
(C) Less than 50 percent fixation (2 plus) in a dilution of 1:10—brucellosis negative.
(iii) Official vaccinates vaccinated with an approved brucella vaccine other than a Brucella abortus Strain 19 approved brucella vaccine:
(A) Fifty percent fixation (2 plus) in a dilution of 1:20 or higher—brucellosis reactor;
(B) Fifty percent fixation (2 plus) in a dilution of 1:10 but less than 50 percent fixation (2 plus) in a dilution of 1:20—brucellosis suspect;
(C) Less than 50 percent fixation (2 plus) in a dilution of 1:10—brucellosis negative.