Objective  To understand the capability and performance of laboratory detection of brucellosis in medical institutions in Gansu province from 2018 to 2022, and its influence on the sensitivity of brucellosis surveillance system, and provide evidence for the development of brucellosis prevention and control measures.

Methods Stratified random sampling method was used to select 11 counties (districts) in 7 prefectures of Gansu for a field investigation of the capability of brucellosis detection and a retrospective survey of the performance of brucellosis detection in county-level medical institutions from 2018 to 2022. The incidence data of brucellosis were collected from the infectious disease surveillance system. The correlation between the number of brucellosis tests and the reported incidence of brucellosis in county-level medical institutions was analysis.

Results  The prefectural (municipal) and county-level centers for disease control and prevention (CDC) surveyed all had the capability of primary screening and confirmation test, but only 57.14% and 9.09% of the CDCs could conduct etiology test respectively. In prefectural (municipal) hospitals, 60.00% of general hospitals and 16.67% of specialized hospitals had the capability of brucellosis diagnosis test and etiology test. In county-level hospitals, 45.45% had the capability of primary screening and diagnosis test of brucellosis. Only 4.55% of the township health centers had the capability of the primary screening test of brucellosis. The correct rate of the blind sample test of the prefectural (municipal) and county CDCs was above 95.24%. From 2018 to 2022, the proportion of county-level medical institutions carrying out diagnosis test of brucellosis in increased from 8.70% to 43.48%, the number of annual tests increased from 55 to 13 465, the number of positive tests increased from 39 to 3 220 , and the positive rate decreased from 70.91% to 23.91%. The sensitivity of the brucellosis surveillance system in Gansu increased, and the reported incidence of brucellosis increased from 5.77/100 000 in 2018 to 20.03/100 000 in 2022. There was a strong positive correlation between the number of brucellosis tests and the reported incidence of brucellosis in Gansu (r=0.981, P<0.01).

Conclusion  The medical institutions at or below county level had lower capability of brucellosis laboratory test in Gansu. In recent years, the actual prevalence of human brucellosis in Gansu was higher than that reported by the surveillance system. It is suggested to further improve the detection capability of brucellosis in primary medical institutions, and strengthen the prevention and control of the infection source.