Table 1.

Comparison of traditional serologic assays for the diagnosis of brucellosis in dogs.

Test	Antigen	Sensitivity	Specificity	How to use test
Rapid Slide Agglutination Test (RSAT)	B. ovis (27,28) (M-) strain B. canis (29)a	Moderate to high sensitivity — older studies suggest high (30,31) — newer study suggests 70.58% (32)	Low to moderate specificity — older studies suggest 40%–50% (27,30) — newer studies suggest 83.34% (32)	Screening test (1,7,8)
2-MercaptoEthanol Rapid Slide Agglutination Test (2ME-RSAT)	(M-) strain B. canis (8)	Lower sensitivity than RSAT 31.76% versus 70.58% (32)	Higher specificity than RSAT 100% versus 83.34% (32)	Confirmatory test (1,7,8)
Tube Agglutination Test (TAT)	B. canis (8)	High sensitivity (1,8)	Low specificity (1,8)	Screening testb (1,7,8)
Indirect Fluorescent Assay (IFA)	Anti-canine immunoglobulin (Ig)G directed against antibodies to B. canis	Unknown sensitivity (7)	Unknown specificity	Screening test (1,8)
Agar Gel Immunodiffusion Assay using Cell Wall Antigen (AGIDcwa)	Lipopolysaccharide antigen from the cell wall of B. canis (8,36)	High sensitivity (1,7,8)	Lower specificity than AGIDcpa (37)c	Screening test (1,8)
Agar Gel Immunodiffusion Assay using CytoPlasmic Antigen (AGIDcpa)	LPS-free, soluble, internal cytoplasmic proteins extracted from B. canis or B. abortus (8,36)	Low sensitivity — 52.94% sensitive (32) — 47.06% false negatives (32)	High specificity 100% (32,37)d	Confirmatory test (1,8)

^aFalse positives — 10% using B. canis antigen versus 50% using B. ovis antigen.

^bResults are semiquantitative (8,30,33–35) with a titer of: > 1:200 — has a good correlation with the organism being recovered from blood culture; 1:200 — presumptive of active infection; 1:25, 1:50 — recovery or chronic infection.

^cFalse positives occur due to nonspecific cross reactions with cell wall antigenic complexes.

^dReacts with antibodies against Brucella spp. (B. canis, B. abortus, B. suis); therefore, specific to the Brucella genus but not individual species.