Objective
To investigate the comparability of compete blood count (CBC) among 30 hospitals in Shijiazhuang in order to provide a reference for mutual recognition of test reports for outpatient laboratories from different hospitals.
Methods
Single-blind survey was designed for this research. Firstly, 62 ml fresh morning blood sample using ethylene diamine tetraacetic acid as anticoagulant was collected from a healthy person and packed to 31 tubes. One of those was measured by the calibration laboratory of hematology analysis in Chinese National Center for Clinical Laboratories as real result which could be traceable to reference method. The outpatient laboratories in 30 hospitals (including 11 tertiary hospitals and 15 secondary hospitals and 4 other unranked hospitals) were investigated using the other 30 samples. Five parameters of CBC were taken to evaluate the results including white cell count (WBC), red cell count (RBC), hemoglobin (Hb), hematocrit(HCT) and platelet (PLT). Results of 11 tertiary hospitals and 15 secondary hospitals were evaluated by group t test statistical analysis. Deviation between the real result and single-blinded results from 30 outpatient laboratories were analyzed to evaluate the comparability of CBC in different hospital. Information of test equipment and external quality assessment (EQA) was collected.
Results
There were 2 [(6.7%(2/30)] hospitals unqualified in RBC, 3 [10%(3/30)] hospitals in Hb and 8 [26.7%(8/30)] hospitals in HCT according to the acceptable range of biological variation provided by Clinical Laboratory Improvement Amendments (CLIA’88). The results of CBC between tertiary hospitals [parameter range: WBC (5.0-5.6)×109/L, RBC (5.3-5.6)×1012/L, Hb (156.7-169.1) g/L, HCT (46.1-52.1)%, PLT (238.0-286.0)×109/L] and secondary hospital [parameter range: WBC(4.5-5.6)×109/L, RBC (5.0-5.9)×1012/L, Hb (150.0- 171.0)g/L, HCT 42.0%-52.0%, PLT (215.0-296.0)×109/L]were analyzed using Student' s t test with the 0.05 confidence level accepted as significant and proved to be not statistically significant (t=1.44, 0.01, 0.91, 1.93, 0.20, respectivily, P＞0.05). According to the survey of test instruments, Sysmex blood analyser was most popular machine in these laboratories, accounting for 57% (17/30).Others were Mindray blood analyzer accounting for 23% (7/30), ABX blood cell counter 10% (3/30), Beckman Coulter Company 7% (2/30) and Thermo Fisher Scientific Company 3% (1/30). No central tendency of laboratory instruments was found in the survey, inferring that the reasons of unqualified laboratories were not the difference of detection systems. Investigation of CBC EQA in 2012 showed there were only 2 laboratories failed among these 30 hospitals. The survey results was not consistent with this investigation.
Conclusions
Through this investigation,good consistency of CBC test in different levels of hospitals in Shijiazhuang city is revealed. Single-blind test is conducive to discover the actual situation in the clinical laboratories, which could be helpful to perform mutual recognition among test results from different clinical laboratories in local district positively.