VDRL (Venereal disease research laboratory) and TPHA(Treponema pallidum
hemagglutination) tests were carried out to evaluate the BFP (biological false positives)
for non-treponemalantigen tests in leprosy patients admitted in Sorok National
Leprosarium.
The results were obtained as follows:
1. VDRL qualitative tests: Of 167 leprosy patients, 26 patients (15.6%) gave the positive
VDRL reactions, which were graded as weakly reactive in 19 patients(11.4% ), and
reactive in 7 patients (4.2%).
2. VDRL quantitative tests: Of the 26 leper's sera which gave the positive VDRL
quantitative tests, the titer was 1 : 1 in 18 sera (69.2%), 1 ; 4 in 2 sera (7.7%), and 1 :
8 in 2 sere (7.7%).
3. TPHA tests : Of the VDRL-reactive 26 lepers, 12 patients (46.2%) showed positive
reactions and the other 14 lepers (53.8%) gave the negative reactions in TPHA testy.
TPHA-negative reactions were observed in the patients giving the positive VDRL
quantitative reactions in 1 : 1, and 1 : 2. But all of those giving reactivity in 1 : 4 or
above gave the positive TPHA tests.
TPHA tests revealed that the 53. 8% of VDRL-reactive lepers in qualitative rests gave
the positive reactions possibly due to BFP and these BFP might be excluded by
concomittant VDRL quantitative tests.
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