Active substances: Doxycycline
Figure 1. Table 3.
Mousa et al. The pre-absorption of rheumatoid factor was made in the sera samples from the patients of our series according to the instructions from the manufacturer of the commercial kit used.
Possible variability in the determination of antibodies between different commercial kits must be taken into account. Faadel et al. They used patient sera from Egypt and the United States. Furthermore, slight differences in specificity were observed among patients from different locations, being slightly higher for sera from patients from Egypt.
False negatives can occur in cases of acute and early disease. It is therefore recommended the pre-absorption of these human sera to determine IgM antibodies. Naha K et al.
Possibly in this case, the use of extracts of lipopolysaccharide of B. This is a retrospective study and therefore it is subject to some limitations. In most of the patients, it was not possible confirm the ELISA results by using other microbiological diagnostic methods.
We also cannot rule out any false negative in determining IgG, mainly in those patients with previous brucellosis.
Furthermore, our study reflects the real conditions in which clinical practice develops. We therefore believe that our results are valid and with clinical interest in the interpretation of Brucella serology by ELISA.
In conclusion, the detection of anti-Brucella IgM antibodies should not be regarded as definitive in the diagnosis of this infection. Prior to accepting this result as a true positive, the test should be repeated after pre-absorption of rheumatoid factor.
Moreover, this finding should always be evaluated within the appropriate clinical history and epidemiological context and confirmed using another diagnostic method such as Brucella agglutination assay, as recommended by CDC.
Our findings support the conclusion that, after detection of IgM anti-Brucella antibodies, the diagnosis of brucellosis must be confirmed by other methods. References 1.
Lancet Infect 6: 91—99. Drugs 53: 245—256. J Clin Microbiol 51: 3055-3062.