Berger-Khan Test for Syphilis

Answer 1

THE BERGER-KHAN TEST FOR

SYPHILIS

BY

J. H. FODDEN, M.D.

AND

E. J. MADDOX, F.I.M.L.T.

(From the Donaldson-Hudson Pathological Laboratories,

Shrewsbury)

Whilst using the dye isamine blue as an indicator in

serological tests for syphilis Berger (1943) found that certain

other dyes when mixed with a suitable alcoholic heart

extract caused, in syphilitic sera, not only the formation of

coloured precipitates but an increase in the sensitivity of

the reaction. This sensitivity was directly proportional to

the amount of dye present in the antigen. Janus green

and Victoria blue were the dyes of choice, as they appeared

to be the best sensitizers and in their presence heavy

flocculation rapidly occurred. The precipitate was intensely

coloured and took up all the dye from the solution, leaving

a water-clear supernatant fluid. Sera containing amounts

of syphilis antibody too small to react with a given antigen

without dye showed marked flocculation in the

presence of Victoria blue or Janus green. Berger pictured

the sensitizing action of the dye as an antibody-like effect conditioned by the presence of a specific factor in syphilitic

serum. In the dye test he devised for syphilis Berger chose

Victoria blue because very fine dispersion of the alcoholic

antigen could be obtained with this dye as compared with

Janus green.

For the purpose of the investigation this laboratory

carried out in triplicate 970 routine serological tests for

syphilis. The washed-antigen method of Price (1946) was

also used for a short time, but in our hands appeared to

be too sensitive. We therefore discontinued parallel tests

to avoid undue complications in the interpretation of

results.

The standard antigen for the Kahn test as supplied by

the Ministry of Health Special Laboratories was, used. The

preparation of reagents and the technique of the test as

recommended by Berger were carried out in the following

manner.

A stock antigen (which keeps for at least a year at room

temperature) is prepared thus: To 10 parts of standard

antigen containing 0.6% of cholesterol and having a titre

of 1 + 1.2 add 1 part of tinct. benz. co. B.P. To 10 ml. of

this mixture add 17 mg. of Victoria blue 4R (Gurr). The

container should be kept well stoppered.

Answer 2

The Berger-Kahn test for syphilis is a serological test used to detect antibodies produced in response to the bacteria that causes syphilis. It is an indirect test, meaning it does not directly detect the presence of the bacteria. The test measures the levels of specific antibodies in the blood and can help diagnose both active and past infections of syphilis.