Abstract: Objective To compare the cost of solid culture, drug susceptibility test and Xpert Mtb/RIF test in the primary laboratories in China. Methods We collected the cost data of solid culture for 3 times and Xpert Mtb/RIF test from 4 county (district) level laboratories, and strain identification and rifampin (RFP) susceptibility test for 3 times from 2 province reference laboratories. The element method was used to calculate the unit cost of each method, the detection cost of each patient. Of the population with different TB prevalence rate, the solid culture was used as the gold standard to compare the cost of Xpert Mtb/RIF test to find 1 TB patient under different detection efficiency. Of the population with different rifampicin-resistant prevalence rate, the traditional drug susceptibility test was used as the gold standard to compare the cost of Xpert Mtb/RIF test to find 1 RFP-resistant patient under different detection efficiency. After price adjustment of Xpert Mtb/RIF detection equipment and reagents, the unit cost of Xpert Mtb/RIF test was analyzed. Results The unit costs of solid culture, strain identification, RFP susceptibility test and Xpert Mtb/RIF detection were 47.87, 46.73, 82.86 and 118.62 Yuan, respectively. The cost per TB patient by traditional methods (2 solid cultures, 1 sub-culture, 1 PNB strain identification) was 172.57 Yuan. The average cost of each patient with drug-resistant TB by traditional methods (2 solid cultures, 1 sub-culture, 1 PNB strain identification and 1 drug susceptibility test) was 208.84 Yuan. When the specificity of Xpert Mtb/RIF test for the detection of Mtb and RFP was 85%, its sensitivity is greater than 70%, its cost of detecting one TB case or RFP-resistant case among the population with 1% to 70% prevalence rate of TB or RFP resistance was lower than traditional methods. The influence of reagent price changes on the testing cost was far greater than the change of equipment price. Conclusion The Xpert Mtb/RIF test is a rapid and more economic method than traditional tests, and suitable for the use in the primary laboratories.

Key words: Mycobacterium tuberculosis, Rifampin, Drug resistance, bacterial, Nucleic acid amplification techniques, Costs and cost analysis