[Can the Brucellacapt test be substituted for the Coombs test in the diagnosis of human brucellosis?].

BACKGROUND

Throughout this work we have studied the capacity of Brucellacapt test to replace Coombs test in the serological diagnosis of human brucellosis.

METHODS

A total of 66 initial sera from patients with diagnostic of brucellosis were studied. The patients were divided in two groups: 42 patients showing a primo-infection (group1), and 24 patients with a previous case of brucellosis (group 2). As a controls, for the group 1 we have used 100 sera from healthy donors, and for group 2, 28 sera from people that have had clinical brucellosis but actually are in good health. All serum samples were tested in either Coombs and Brucellacapt tests. The diagnostic yield was calculated using ROC (receiver-operating characteristic) plots.Moreover, the results obtained in Coombs and Brucellacapt tests with 397 serum samples from 66 patients with brucellosis were compare with a non-parametric method.

RESULTS

The sensibility and specificity for group1 were respectively 1 and 0.98 for Coombs and, 1 and 0.95 for Brucellacapt tests. For group 2, the results in Coombs test were 1 and 0.80, and in Brucellacapt test 0.95 and 0.74. In this second group, the area under the ROC plot was 0.950 for Coombs and 0.904 for Brucellacapt tests. Non statistical differences were observed comparing both serological tests using the Wilcoxon method (Z= -0.213; p=0.8).

CONCLUSIONS

Brucellacapt and Coombs tests yield similar diagnostic results in the follow-up of serological samples from patients with brucellosis, and its should consider as interchangeables.