Quality assurance and application of secondary standard hematology analyzer for platelet enumeration

Objective To evaluate the accuracy and comparability of secondary hematology analyzer for platelet enumeration in order to determine the accuracy and reliability of assigned value of fresh blood.Methods The results between secondary standard hematology analyzer and the reference method of platelet enumeration of 40 specimens were compared according to the document from CLSI EP9-A2.The correlation and bias were calculated.At the same time,the results of secondary standard hematology analyzer between our laboratory and Japan reference laboratory were compared.The fresh blood from normal people was prepared to be used as calibrator after assigned value by secondary standard hematology analyzer.And 36 hematology analyzers were performed correctness validation and calibrated by 36 fresh bloods.Results The results of 40 specimens by secondary standard hematology analyzer and the reference method were ( 108 -326) × 109/L and( 110 -327 ) × 109/L respectively.Correlation coefficient between the secondary standard hematology analyzer and the reference method was 0.993.The bias between two methods was from -3.8％to 3.4％.The results of NCCL and Japan reference laboratory from 2009 to 2010 were( 185 -203) × 109/L and (185 - 198) × 109/L The bias range between our laboratory and reference laboratory in Japan was from - 1.4％ to 3.7％.The ranges of coefficient variations of two laboratories were from 2.0％ to 3.0％ and from 2.6％ to 3.4％,respectively.The biases of 20 hematology analyzers were from - 2.6％ to 2.1％ and they passed the correctness validation.The biases of 16 hematology analyzers were decreased from 3.4％ - 12.6％of pre-calibration to 0％ - 2.8％ of post-calibration.Conclusions The results of secondary standard hematology analyzer are assured to be accurate and comparable by the comparison of reference laboratories.It is feasible that fresh blood assigned value by secondary standard hematology analyzer can be used as calibrator for the hematology analyzer. Key words: Reference standards;  Platelet count;  Calibration;  Reproducibility of results