Evaluation of low platelet counts by optical, impedance, and CD61-immunoplatelet methods: estimation of possible inappropriate platelet transfusion.
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.
Cid
Joan
J
Hematology Service, Hospital Universitari Joan XXIII, IISPV, Universitat Rovira i Virgili, Tarragona, Spain. jcid.hj23.ics@gencat.cat
Nascimento
Janilson Do
JD
Vicent
Ana
A
Aguinaco
Reyes
R
Escoda
Lourdes
L
Ugarriza
Aranzazu
A
Llorente
Andreu
A
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
D015703:Antigens, CD; D039661:Integrin beta3