title: Decreased sensitivity of the automatic white precursor cell channel (WPC) for blast flagging in patients with leukopenia.
abstract: OBJECTIVE
  The advantage of Sysmex XN system is its performance of an automatic reflex test in white cell precursor (WPC) channel, which gives an accurate differential count. We performed a real-time evaluation of the automatic differential count according to WBC number with Sysmex XN series and demonstrated a significant differential impact on blast distinction depending on the number of WBC.
  
  
  METHODS
  We categorized the 49,699 specimen according to WBC number and compared the results of blast flagging in the white cell differential (WDF) channel and WPC channel on the basis of the results of manual differential count. Additionally, clinical impact of missed blasts after running WPC reflex test was analyzed.
  
  
  RESULTS
  For patients with WBC under 1.5×10(9)/L, blast flagging for WPC channel showed markedly decreased sensitivity (56%) compared to that of WDF mode (100%). Most of the patients with missed blasts in WPC mode were under chemotherapy or hematopoietic stem cell transplantation. The specificity and efficiency for WPC channel were much higher than that of WDF mode in all range of WBC.
  
  
  CONCLUSIONS
  Considering the additional reagent cost required for the WPC channel, WPC reflex test is not suitable for patients with leukopenia if it is operated alone. Instead, manual blood film review or double-check with other supplemental equipment should be accompanied.
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Nuri
authors.initials: N
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Ju Hyun
authors.initials: JH
authors.lastname: Jun
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, South Korea. Electronic address: soonlee@snu.ac.kr.
authors.forename: Dong Soon
authors.initials: DS
authors.lastname: Lee
mesh_terms: D057205:Automation, Laboratory; D015415:Biomarkers / Q000032:analysis*; D001752:Blast Crisis / Q000175:diagnosis*; D005434:Flow Cytometry / Q000295:instrumentation*; D006801:Humans; D007958:Leukocyte Count / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D007962:Leukocytes / Q000473:pathology*; D007970:Leukopenia / Q000175:diagnosis*; D011379:Prognosis
chemical_list: D015415:Biomarkers
keywords: Leukopenia; Performance evaluation; Sysmex XN; WDF; WPC