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Test ID BRCMG Brucella Antibody Screen, IgM and IgG, ELISA, Serum

Specimen Required

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Useful For

Evaluating patients with suspected brucellosis

Profile Information

Test ID Reporting Name Available Separately Always Performed
BRCM Brucella Ab Screen, IgM ELISA, S No Yes
BRCG Brucella Ab Screen, IgG ELISA, S No Yes
BRCI Brucella Ab Screen Interpretation No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
BRUTA Brucella Ab, Agglutination, S Yes No

Testing Algorithm

If Brucella antibody screen, IgM or IgG is either positive or equivocal, then confirmation by Brucella total antibody agglutination testing will be performed at an additional charge.

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

Brucella Ab Screen, IgM/IgG ELISA, S

Specimen Type


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Clinical Information

Brucellosis, major disease in humans and domesticated animals, is a systemic bacterial infection caused by Gram negative coccobacilli of the genus Brucella. Brucellosis is a zoonotic disease and a variety of domestic animals serve as reservoir species: Brucella infects goats (Brucella melitensis), cattle (Brucella abortus), swine (Brucella suis), and dogs (Brucella canis). Transmission to humans results from direct contact with infected animals, exposure to infectious aerosols, or ingestion of unpasteurized dairy products; human-to-human transmission does not occur. While few cases are reported in the US, the majority of cases occur in the Mediterranean region, Western Asia, and parts of Latin America and Africa. Three species of Brucella commonly cause disease in humans: B melitensis, B suis, and B abortus. Clinical manifestations of brucellosis consist of fever, sweats, malaise, weight loss, headache, and weakness. The onset may be insidious or acute, generally beginning within 2 to 4 weeks after exposure. Any organ or system of the body may be involved, although death is uncommon. Presumptive diagnosis of brucellosis can be made by detection of high or rising titers of specific antibodies, typically to smooth lipopolysaccharide (S-LPS), a major antigenic virulence determinant. Serologic tests using S-LPS can detect antibody to the three major Brucella species due to this shared epitope. IgM antibodies appear during the first week of infection followed by a switch to IgG synthesis during the second week. A variety of serologic tests have been used for diagnosis of Brucella infection. Detection of anti-Brucella antibodies using ELISA has been demonstrated to be a sensitive diagnostic approach. However, all specimens testing positive by an ELISA should be confirmed by an agglutination method as a means to increase assay specificity.

Reference Values






Reference values apply to all ages.


In the acute stage of the disease, there is an initial production of IgM antibodies followed closely by production of IgG antibodies. IgG-class antibodies may decline after treatment; however, high levels of circulating IgG-class antibodies may be found without any active disease.


Rising levels of specific antibody in paired sera can be regarded as serological evidence of recent infection. The presence of specific IgM in a single specimen may also indicate a recent infection, although IgM-class antibodies may persist for months following acute disease.


The CDC recommends that specimens testing positive for IgG or IgM by ELISA be confirmed by a Brucella-specific agglutination method.(1)


The CDC/Council of State and Territorial Epidemiologists case definition for human brucellosis states that the laboratory criteria for diagnosis includes 1) isolation of Brucella species from a clinical specimen, 2) four-fold or greater rise in Brucella agglutination titer between acute- and convalescent-phase serum specimens obtained more than 2 weeks apart and studied at the same laboratory, and/or 3) demonstration by immunofluorescence of Brucella species in a clinical specimen.


Positive results by ELISA that are not confirmed by Brucella-specific agglutination may represent false-positive screening results. If clinically indicated, a new specimen should be tested after 14 to 21 days.


If results of ELISA are negative and a recent infection is suspected, a new specimen should be tested after 14 to 21 days.

Clinical Reference

1. Public health consequences of a false-positive laboratory test result for Brucella-Florida, Georgia, and Michigan, 2005, MMWR Morb Mortal Wkly Rep 2008 Jun 6;57(22);603-605

2. Gunes H, Dogan M: False-positivity in diagnosis of brucellosis associated with Rev-1 vaccine. Libyan J Med 2013;8:20417

3. Corbel MJ: Brucellosis: an overview. Emerg Infect Dis 1997;3:213-221

4. Araj GF, Lulu AR, Saadah MA, et al: Rapid diagnosis of central nervous system brucellosis by ELISA. J Neuroimmunol 1986;12:173-182

Day(s) and Time(s) Performed

Monday, Wednesday, Friday; 9 a.m.

Analytic Time

Same day/1 day - Additional days for agglutination test result if reflex testing is required.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

86622 x 2-Brucella antibody, IgG and IgM

86622-Brucella total antibody, agglutination (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BRCMG Brucella Ab Screen, IgM/IgG ELISA, S 91140-4


Result ID Test Result Name Result LOINC Value
BRCM Brucella Ab Screen, IgM ELISA, S 24388-1
BRCG Brucella Ab Screen, IgG ELISA, S 24387-3
BRCI Brucella Ab Screen Interpretation 66485-4