DIRECTIONS OF USE :
Five tubes are normally used for each serum under test. Phenol saline (0.85 % Nacl solution containing 0.5% of phenol) is placed in each tube, 0.8 ml in the first and 0.5 ml in each succeeding tube: 0.2 ml of the serum under test is placed in the first tube and mixed thoroughly with the phenol saline already there; 0.5 of the mixture is carried over the second tube; from which; after mixing 0.5ml is transferred to the third tube, and so on. This process is continued until the last tube , from which, after mixing, 0.5 ml of the serum dilution is discarded. This process of doubling dilutions results in 0.5 ml of dilutions 1:5, 1:10 , 1:20 and so on, in each tube. To each tube is then added 0.5 ml of antigen at the recommended dilution and the contents of the tube thoroughly mixed, thus giving final serum dilution of 1:10, 1:20, 1:40, etc.

READING THE TEXT :
With the above technique, using an antigen standardized to give 50% agglutination with a 1:500 dilution of the international standard Anti Brucella abortus serum, the evaluation of the results should be as follows:
In non-vaccinated cattle: attire of 1:40 (i.e. 50% agglutination at 1:40) or above indicates an infected animal, and attire of 1:20 is regarded as suspicious reaction. With the technique described, a serum having a titre of 1:40 contains 80 international units permilliter, and one having titre of 1 : 20 contains 40 IU/ML.

N.B. For testing the sera of sheep and goats it is advised that a 5% Nacl
solution containing 5 % of phenol be used both for making the serum dilutions and for dilution the antigen concentrate. This procedure reduces the occurance of prozones.

PRECAUTIONS :
* Shake the bottle very well before use.
* Dilute the antigen as recommended on the label.
* Use fresh diluted antigen as possible as you can.
* To ensure validity of the antigen use control positive and negative sera.