Regarding to diagnosis for bovine brucellosis, more than one serological test should be conducted to confirm the infection by Brucella with a reliable result due to various factors including false positive serological reactions. In this study, we compared confirmatory serological tests to determine the appropriate way to detect and confirm the Brucella infection in South Korea. Several serological tests, including serum agglutination test (SAT), indirect (I)- and competitive (C)-ELISA, and fluorescence polarization assay (FPA), for detection of bovine brucellosis were performed with sera from 537 cattle. In addition, comparison of diagnostic efficacy was performed with bacterial isolation represented true positive. Of 537 serum samples, 426 (79.3% of prevalence), 433 (80.6%), 414 (77.1%), and 409 (76.2%) sera were positive for SAT, C-ELISA, I-ELISA, and FPA respectively. Based on the results of serology, the correlation among the serological tests revealed observed agreements of more than 92% with kappa (k) value of more than 0.77. The correlation between serological tests with bacterial isolation appeared observed agreements of between 79.9% and 84.7% with k value of between 0.42 and 0.59. Particularly, FPA recorded almost perfect agreements with C-ELISA and I-ELISA as well as the highest correlation with bacterial isolation. Accordingly, this investigation presented the comparison of correlation and diagnostic efficacy of serological tests for bovine brucellosis in South Korea. We suggest this finding will be a useful data to re-establish the potential serological diagnostic methods that can apply to maintain the low prevalence.

INTRODUCTION
MATERIALS AND METHODS
    Study area and study design
    Collection of samples
    Serological tests
    Bacterial isolation and identification
    Statistical analysis
RESULTS
    Serological determination
    Comparison of correlation in serological tests
DISCUSSION
ACKNOWLEDGEMENTS

• Ah-Ryeong Joe(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea)
• Jin Ju Lee(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea) Corresponding Author
• Eun Ji Yum(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea)
• Yoon-Jeong Seo(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea)
• So-Ra Sung(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea)
• Jeong-Soo Choi(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea)
• Soon-Seek Yoon(WOAH Reference Laboratory for Brucellosis, Bacterial Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, 39660, Korea)