The agglutination reaction in the diagnosis of tuberculosis

Abstract

Many attempts have been made in the past to make use of the agglutination reaction in the diagnosis of tuberculosis. The test has been found unsatisfactory largely because of the fact that the tubercle bacilli grow in adherent masses from which it has been difficult to prepare the homogeneous suspensions necessary for carrying out the test.

In the year 1918 Larson, Hartzell and Diehl 1 described a method of emulsifying and disrupting bacteria by subjecting them to the influence of carbon dioxide under high pressure, after which the pressure was suddenly released, causing a disruption of the organisms as a result of the rapid escape of the gas with which they were filled.

Tubercle bacilli grown on glycerine broth or glycerine agar are suspended in distilled water and placed in the apparatus where they are subjected to CO₂ pressure for two or more hours. The process may be repeated as often as desired although one treatment, as a rule, is sufficient to effect emulsification. By repeating the process several times a large percentage of the organisms may be disrupted. After the CO₂ treatment the emulsion is diluted to the desired standard with salt solution. In this way a perfectly homogeneous suspension of tubercle bacilli, which gives no sediment after standing several days without agitation, may be obtained. The addition of 0.2 per cent. trikresol enables the suspension to be kept in the laboratory indefinitely.

We have performed the agglutination reaction on three hundred cases, one hundred of which were known to have tuberculosis, and two hundred “normal “ cases. With one exception all of the tubercular cases gave agglutination. Of the “normals “ all but five gave a negative reaction. Of the cases five which gave the positive reaction four were suspected of having syphilis but only one of these had ever given a positive Wassermann.