title: Evaluation of low platelet counts by optical, impedance, and CD61-immunoplatelet methods: estimation of possible inappropriate platelet transfusion.
abstract: BACKGROUND
  The Cell-Dyn Sapphire (Abbott Diagnostics) detects platelets (PLTs) with a CD61 monoclonal antibody directed against glycoprotein IIIa as well as impedance (IMP) and optical (OPT) technology. We decided to evaluate low PLT counts produced by IMP and OPT methods and to compare them with the CD61 method. We also examined the possibility of inappropriate PLT transfusion resulting from an inaccurate PLT count.
  
  
  METHODS
  We analyzed consecutive blood samples with OPT PLT counts of less than 50 x 10(9)/L. We performed the PLT count with the OPT, IMP, and CD61 methods and we compared the number of prophylactic PLT transfusion indications according to the PLT counts determined by the OPT and IMP methods with the number of prophylactic PLT transfusion indications according to our reference CD61 method.
  
  
  RESULTS
  We collected 135 samples. In the bias analysis, the OPT method and the IMP method showed higher PLT counts when compared with the CD61 method (mean of difference 1.69 x 10(9) and 19.1 x 10(9)/L, respectively). We saw overtransfusion in 1.5% of cases and undertransfusion in 15.2% of cases (p = 0.01; McNemar's test) when we selected a threshold of 10 x 10(9)/L with the OPT method. We saw undertransfusion in 22.2% of cases (p = 0.03; McNemar's test) when we selected a threshold of 5 x 10(9)/L with the OPT method.
  
  
  CONCLUSIONS
  Low PLT counts determined by the OPT and IMP methods showed some disagreement when compared with the CD61 method. This disagreement caused both PLT undertransfusion and overtransfusion.
authors: Hematology Service, Hospital Universitari Joan XXIII, IISPV, Universitat Rovira i Virgili, Tarragona, Spain. jcid.hj23.ics@gencat.cat
authors: Joan
authors: J
authors: Cid
authors: Janilson Do
authors: JD
authors: Nascimento
authors: Ana
authors: A
authors: Vicent
authors: Reyes
authors: R
authors: Aguinaco
authors: Lourdes
authors: L
authors: Escoda
authors: Aranzazu
authors: A
authors: Ugarriza
authors: Andreu
authors: A
authors: Llorente
mesh_terms: D015703:Antigens, CD / Q000097:blood; D001792:Blood Platelets / Q000276:immunology*; D003131:Combined Modality Therapy; D006402:Hematologic Diseases / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D006801:Humans; D039661:Integrin beta3 / Q000097:blood*; D010976:Platelet Count / Q000379:methods*; D017713:Platelet Transfusion / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015703:Antigens, CD; D039661:Integrin beta3