title: Evaluation of paroxysmal nocturnal hemoglobinuria screening by flow cytometry through multicentric interlaboratory comparison in four countries.
abstract: OBJECTIVE
  Paroxysmal nocturnal hemoglobinuria (PNH) is currently diagnosed by flow cytometry; although highly sensitive, its interpretation and reporting appear as critical as its technique. Thus, we developed a quality control scheme for the French-speaking region based on the international recommendations for PNH screening.
  
  
  METHODS
  After a topical workshop, we proposed a 1-year, two-step survey program to any volunteering French-speaking clinical laboratory. The first survey consisted of sending raw data files to evaluate gating and the interpretation strategy of each center. The second stipulated sending fresh whole-blood samples to evaluate the whole process and its practice.
  
  
  RESULTS
  Forty-nine participants from voluntary centers returned results for each of the two successive surveys. On virtual survey, 27% reported false-positive PNH created by immature granulocytes, whereas the minor PNH clone was not detected by 9%. On fresh survey, 63% of centers used at least the same six-color combination (CD24, CD14, CD33, CD15, CD45, and fluorescent aerolysin), and nearly 70% of participants were able to perform a sensitivity test less than 0.1% on neutrophils. All participants detected the major PNH clone, yet 16% returned false-positive results for the non-PNH clone case.
  
  
  CONCLUSIONS
  We succeeded in rallying numerous French-speaking clinical laboratories for both surveys and in harmonizing the technical practice by highlighting common pitfalls.
authors.affiliation: From Laboratoire d'Hématologie, CH Mulhouse, Mulhouse, France;
authors.forename: Agathe
authors.initials: A
authors.lastname: Debliquis
authors.affiliation: Département d'Hématologie et d'Immunologie Biologiques, Hôpitaux universitaires Henri Mondor, APHP, UPEC, Créteil, France;
authors.forename: Orianne
authors.initials: O
authors.lastname: Wagner-Ballon
authors.affiliation: Service d'Hématologie Biologique, Groupe Hospitalier Pitié-Salpêtrière-Charles Foix, APHP, Paris, France;
authors.forename: Magali
authors.initials: M
authors.lastname: Le Garff-Tavernier
authors.affiliation: Laboratoire d'Hématologie, CHU La Timone, Marseille, France;
authors.forename: Chantal
authors.initials: C
authors.lastname: Fossat
authors.affiliation: Laboratoire d'Hématologie, CHU UCL Mont-Godinne, Dinant, Belgium; and.
authors.forename: Bernard
authors.initials: B
authors.lastname: Chatelain
authors.affiliation: Laboratoire d'Hématologie, CHU Avicenne Hôpitaux Universitaires de Seine-Saint-Denis, APHP, Université Paris13, Paris, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Letestu
authors.forename: Bernard
authors.initials: B
authors.lastname: Drénou
mesh_terms: D005189:False Positive Reactions; D005434:Flow Cytometry / Q000379:methods* / Q000592:standards*; D006457:Hemoglobinuria, Paroxysmal / Q000175:diagnosis*; D006801:Humans
keywords: Accreditation; Flow cytometry; Interlaboratory comparison; PNH; Robust statistics