The complement fixation test in syphilis, commonly known as the Wassermann test.

  • Great Britain. Ministry of Health.
Date:
1920
Catalogue details

Licence: Public Domain Mark

Credit: The complement fixation test in syphilis, commonly known as the Wassermann test. Source: Wellcome Collection.

    41/218 (page 37)
    Human ‘SERUM (1) Preparation of Serum.—The minimum amount necessary for test by the method proposed is 0°15 c.c., but for convenience in making the dilutions and as a reserve in case of accidents, about 0°5-c.c. should be available ;- this can usually be obtained from 1°5 ¢.c. to 2 c.c. of blood. The serum, which should not be deeply hemoglobin stained, must be freed from blood cells either by centrifuging or by being allowed to stand in the ice-chest. The serum should beso far as possible aseptic. Bacterial contamination often renders serum anticomplementary and therefore useless for the test by. the ice-chest method of fixation. This method reveals anticomplementary properties which might escape notice, though probably equally undesirable, in the ordinary method of fixation. (2) Inactivation.—There is no doubt that fresh serum, with certain antigens at least, may give a positive Wassermann reaction in the absence of syphilitic infection. For this reason it 1s generally agreed that the serum must be inactivated at 56° C. before use. As regards the length of time necessary for inactivation, we have not found that stronger reactions are given by our method after a short period of heating (10 minutes), than after the usual half-hour. Occasionally, indeed, the reaction has appeared to be weaker with the short period: of inactivation, probably on account of the disturbing effect of the incompletely destroyed human complement. Our experiments show that a serum may be heated to a temperature of 56° C. for a much longer period than 30 minutes before its capacity to react is materially reduced. Exposure of serum to a temperature of 56° C. for four hours reduced its capacity to give a positive reaction only very slightly more than exposure for half an hour (Table X.). A serum which had been heated for half an hour at 5€° C., and gave a positive reaction when diluted I in 160, was heated to 60°C. for a further period of 12 minutes. The reaction was reduced in strength, being obtained only in a dilution of 1 in 80, but no further reduction in strength occurred on continuing the heating at, 60° C. for a full hour (Table Al). The slightly greater effect of heating to 66° C. upon two different sera, both strongly positive, is shown in Table X. At 70° C. (again Table X.) the positive reaction was rapidly weakened and disappeared completely after exposure for half- an-hour. In the case of syphilitic cerebro-spinal fluid, while there was a slight diminution in reacting capacity after heating to 56° C. for 15 minutes, no further reduction occurred after an hour’s exposure, and the positive reaction began to fail only at the end of two hours. Cerebro-spinal fluid gradually lost its reacting capacity as the result of exposure to a temperature of 62°C.; after 35 minutes at this temperature the fluid still