Serodiagnosis of Human Brucellosis in Resource-Limited Settings: A Combination of Rose Bengal Plate Test and Standard Agglutination Test

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Agnibho Mondal, Dolanchampa Modak, Rupali Dey,
Swagata Bannerjee, Silpak Biswas, Debashis Koley
School of Tropical Medicine, Kolkata
Serodiagnosis of Human Brucellosis in Resource-Limited Settings:
A Combination of Rose Bengal Plate Test and Standard Agglutination Test
Background
Diagnosis of brucellosis
remains a signicant global
health challenge, parcularly
in regions where resources
are scarce. Although culture
is considered the gold
standard, the isolaon rate is
subopmal.1 Serodiagnosc
test results are oen
inconclusive and dicult to
interpret. A single serological
test is therefore inadequate
for proper interpretaon.2
Methods
We conducted a retrospecve
analysis of laboratory data of
last one year from School of
Tropical Medicine. We
included paents who
presented with compable
clinical features and/or
history of exposure to
domesc animals who
underwent three serological
tests for brucellosis which
included RBPT, SAT and IgM
ELISA from blood. The
reference standard for
comparison was taken to be
the posivity of all three
tests. We compared the
performance of combinaon
of RBPT and SAT (group 1) as
well as combinaon of RBPT
and IgM ELISA (group 2)
Results
In our study 679 paents
were included all of whom
underwent all three
serological tests.
Group 1 and group 2 both
showed near perfect
agreement with the
reference. The Cohen’s
kappa of group 1 was 0.89
while it was 0.95 for group 2.
The accuracy of group 1 was
97.2% (95% condence
interval 95.7 to 98.3)
whereas for group 2 it was
98.8% (95% condence
interval 97.7 to 99.5) with
overlapping 95% condence
interval. McNemar’s test
showed that the two
combinaons were not
signicantly dierent from
each other (p=0.054).
Conclusion
The study establishes the
combined applicaon of
RBPT and SAT is as accurate
but cost-eecve alternave
to combinaon of RBPT and
IgM ELISA for serodiagnosis
of human brucellosis in areas
with limited healthcare
1. Di Bonaventura G et al. Microbiological Laboratory Diagnosis of Human Brucellosis: An Overview. Pathogens. 2021 Dec 14;10(12):1623. doi: 10.3390/pathogens10121623
2. Yagupsky P et al. Laboratory Diagnosis of Human Brucellosis. Clin Microbiol Rev. 2019 Nov 13;33(1):e00073-19. doi: 10.1128/CMR.00073-19
Objecves
The primary aim was to
compare the accuracy of the
Rose Bengal Plate Test
(RBPT) combined with the
Standard Agglunaon Test
(SAT) against the
combinaon of RBPT and
IgM ELISA.
Conngency Table: Reference (all 3) vs RBPT & ELISA
Reference
Posive Negave Total
RBPT
&
ELISA
Posive 92 8 100
Negave 0 579 579
Total 92 587 679
Conngency Table: Reference (all 3) vs RBPT & SAT
Reference
Posive Negave Total
RBPT
&
SAT
Posive 92 19 111
Negave 0 568 568
Total 92 587 679
Standard Tube Agglunaon test
Rose Bengal Plate test IgM ELISA
Forest Plot Comparing Accuracy of
Two Groups of Tests
We acknowledge all personnel of Naonal One Health Programme for Prevenon and Control of Zoonosis,
School of Tropical Medicine, Kolkata whose contribuons were invaluable in this study.