title: Intra- and interlaboratory variability of paroxysmal nocturnal hemoglobinuria testing by flow cytometry following the 2012 Practical Guidelines for high-sensitivity paroxysmal nocturnal hemoglobinuria testing.
abstract: BACKGROUND
  Sutherland et al. recently published the Practical Guidelines for high-sensitivity detection of paroxysmal nocturnal hemoglobinuria (PNH) clones by flow cytometry (FCM), containing concise protocols for PNH testing.
  
  
  METHODS
  Using this approach, we studied the intra- and interlaboratory variability observed in a multicenter study in which fresh blood samples containing three clinically relevant PNH clone sizes within the granulocytic, monocytic, and red blood cell (RBC) populations were shipped to each participating center.
  
  
  RESULTS
  Coefficients of variation (CVs) for precision/reproducibility analysis ranged from 0.01%/0.02% to 0.48%/0.45% (big clone), from 0.69%/1.52% to 4.24%/5.80% (small-intermediate clone), from 1.47%/3.91% to 15.01% /17.83% (minor clone) for PNH white blood cells (WBCs) and from 0.24%/0.48% to 1.76%/1.83% (big clone), from 0.80%/1.14% to 2.39%/4.45% (small-intermediate clone), from 1.09%/3.36% to 10.54%/10.23% (minor clone) for PNH RBCs, respectively. Linear regression analysis showed excellent performance correlation between centers (r > 0.99), Wilcoxon rank test revealed no statistically significant differences for PNH granulocytes, monocytes, and RBCs (P > 0.05%), Bland-Altman analysis demonstrated good performance agreement for all target PNH clones (mean bias ranging from -1.47 to 0.71).
  
  
  CONCLUSIONS
  Our results demonstrate very good intra- and interlaboratory performance characteristics for both precision and reproducibility analyses and excellent correlation and agreement between centers for all target PNH clone sizes. Our data confirm the reliability and robustness of the recently published Practical Guidelines approach for high sensitivity PNH testing by flow cytometry and suggest that such an approach represents an excellent basis for standardization of PNH testing by flow cytometry.
authors: Institute of Hematology and Blood Transfusion, Prague, Czech Republic. Iuri.Marinov@uhkt.cz
authors: Iuri
authors: I
authors: Marinov
authors: Martina
authors: M
authors: Kohoutová
authors: Vlasta
authors: V
authors: Tkáčová
authors: Daniel
authors: D
authors: Lysák
authors: Monika
authors: M
authors: Holubová
authors: Olga
authors: O
authors: Stehlíková
authors: Tatiana
authors: T
authors: Železníková
authors: Darja
authors: D
authors: Žontar
authors: Andrea
authors: A
authors: Illingworth
mesh_terms: D018957:CD59 Antigens / Q000097:blood*; D004912:Erythrocytes / Q000473:pathology; D005434:Flow Cytometry; D006457:Hemoglobinuria, Paroxysmal / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes / Q000473:pathology; D017410:Practice Guidelines as Topic; D012015:Reference Standards
chemical_list: D018957:CD59 Antigens