Abstract: ObjectiveTo investigate effects of anticoagulant,sample preparation,storage temperature and time on detection of circulating microparticles(MPs).MethodsThe blood samples of 40 systemic lupus erythematosus and 41 rheumatoid arthritis inpatients from the Second Affiliated Hospital of Soochow University,and 52 healthy donors were collected.MPs of the samples treated with different anticoagulants(sodium citrate,ethylenediaminetetraacetic acid-dipotassiumEDTA-K₂,heparin),preparation methods(washed platelet-poor plasmaPPP,and directed PPP),storage temperatures(-4 ℃,-20 ℃,-80 ℃),and times(1,3,7,10,and 14 days)were detected with flow cytometer and compared.ResultsThe content of MPs for the samples treated with sodium citrate plasma,EDTA-K2,heparin,and without anticoagulant were 1 527.0±620.4,981.4±247.9,877.7±176.2,and 480.8±112.2 μL, respectively,with significant differences(F=9.11, P<0.01).The MPs content of directed PPP samples from systemic lupus erythematosus patients,rheumatoid arthritis patients,and healthy donors were 1 972.4±2 850.7,3 347.8±3 431.5,and 2 157.7±1 901.1 μL,respectively,and were all higher than those of washed PPP samples(1 406.4±2 205.7,2 375.6±2 500.2,and 1 502.8±1 337.1μL)(all P<0.01).Compared with those of the fresh plasma samples,the MPs content decreased significantly for the samples stored at the temperature of-4 ℃,-20 ℃,and-80 ℃ and stored for 1,3,7,and 10 days (all P<0.05),but the content showed no significant difference when stored for 14 days at the temperature of-4 ℃,-20 ℃,and-80 ℃(all P>0.05);there were also no significant differences in MPs content among the samples with various storage duration(1-14 days)at the three different temperatures(all P>0.05).ConclusionMPs content should be detected for fresh samples treated with EDTA-K2 and without of repeated washing and the storage temperature of-4 ℃,-20 ℃,and-80 ℃ could selected for short time preservation of plasma sample.