Objective To study the situation of missing detection of HBsAg negative samples with high value and to explore the ways for reducing the missing detection .Methods According to the document EP15-A2 issued by the Clinical and Laboratory Standards Institute(CLSI) ,the precision and accuracy of the HBsAg quantitative detection by the ARCHITECT I 2000 were verified for ensuring the instrument conditions conforming to the test requirements .The 1 130 samples with the ratio of the sample absor-bance value to critical value(S/CO) in the range 0 .30-0 .99 in the HBsAg qualitative results by ELISA were collected during the study period and re-tested .After re-testing ,the quantitative HbsAg of 387 samples ,in which the ratio of S/CO was still in the range 0 .30-0 .99 ,were detected by the ARCHITECT I2000 and the detection results were taken as the reference .The missing detection situation of HBsAg negative samples with high value was researched .The ROC curve was adopted to reassess the cutoff value of negative HBsAg with positive HbcAb for searching better diagnostic performance .Results The HBsAg detection results by the i2000SR had good repeatability with total imprecision of less than 9 .88% and the deviation value with calibrator was less than 3 .91% ,which conformed to the clinical testing requirements .This study found that the HBsAg samples with the S/CO ratio of 0 .30-0 .99 had the significant distribution differences in the different batches of test (P<0 .05) .In the study period ,261 cases of HBsAg missing detection occurred ;then the critical value of HBsAg qualitative results detected by ELISA in the HbcAb positive group was re-determined as 0 .51 by using the ROC curve ,among them 239 cases were rejudged as positive .Conclusion Increasing the repeatability of HBsAg qualitative detection by ELISA and establishing the new positive judgement value of ELISA for qualita-tive HBsAg in the HbcAb positive population as 0 .51 possesses better diagnostic performance for detection the HBsAg samples with the S/CO ratio of 0 .30-0 .99 .

Objective To analyze reason and countermeasures of unqualified blood specimens ,improve the qualified rate of sam-ples ,to strengthen the quality control before analysis .Methods A retrospective statistical analysis were conducted to analyze the characteristics of the unqualified specimen and reasons from January 2013 to June 2014 .Results A total of 11 024 unqualified spec-imens accepted in the inspection center from January 2013 to June 2014 ,accounting for 0 .331% of reasons of unqualified specimens including hemolysis(26 .7% ) ,blood coagulation(25 .8% ) .The unqualified specimen in surgical system was higher than that in med-ical system .Conclusion Control specimen qualified rate system should be established in clinical laboratory ,the fraction defective samples should be reduced through continuous analysis and communication with clinical medical personnel to ensure the quality be-fore analyzing .

Objective To analyse clinical application of hepatitis B virus core antibody(HBcAb)detected by using the chemilu-minescence microparticle immunoassay.Methods A total of 1 6 830 specimen with positive HBcAb detected by using the two pairs of semi-hepatitis test from January 2012 to November 2014 were collected,and divided into three groups according to the cut off in-dex(COI)of detection results of HBcAb,including group 1.0-<9.0,group 9.0-<1 1.0 and group COI≥1 1.0,and detection re-sults were statistically analysed.The hepatitis B virus(HBV)DNA test was carried out in specimen with negative hepatitis B surface antigen(HBsAg)and hepatitis B surface antibody (HBsAb)and COI≥1 1.0.Results The detection rate of HBsAg(+)HBsAb(-) (13.84%)was significantly higher than other expression patterns in group ≥1 1.0(P <0.05).There was no statistically significant differences in positive rate among all expression patterns of HBsAg and HBsAb in the group 9.0-<1 1.0(P >0.05).The detec-tion rate of HBsAg(+)HBsAb(-)of group 9.0-<1 1.0 was significantly lower than that of the other two groups(P <0.05).A total of 304 specimen were HBsAg(-)HBsAb(-)and COI≥1 1,among them 64 specimen were HBV DNA postive and the posi-tive rate was 21.0%.Conclusion In the detection of HBcAb,COI≥1 1 and 1.0-<9.0 could be reference indicators for diagnosiing current and past HBV infection respectively,which should be combined with other laboratory indicators of HBV clinical data for comprehensive analysis.