PNH Screen, high sensitivity analysis for PNH, CD59, FLAER, GPI deficiency
Coombs negative hemolytic anemia, myelodyspastic syndromes with unilineage dysplasia and unexplained hemoglobinuria, aplastic anemia, cytopenia or thrombosis;
Flow cytometry, multiparameter analysis
Screen WBC, if any positive finding auto-reflex for RBC component
2.0 mL (min. 0.5 mL) heparin whole blood, EDTA accepted
2.0 mL (min. 0.5 mL) heparin bone marrow aspirate*, EDTA accepted
*Although not a preferred sample type, bone marrow samples are acceptable for detecting most cases of clinically symptomatic disease but are not ideal for detecting very small PNH-like clones, <1-2%
Ship at ambient temperature; Ship in a Styrofoam container with a cool/refrigerated pack (Do not allow cool pack to directly contact sample)
Specimen >48 hours old prior to testing; Specimens stored at incorrect temperature; Non-viable specimens; Specimens in inappropriate anticoagulant; Too few cells; Excessive hemolysis; Specimen clotted
Normal = no evidence of PNH population
Positive = > 0.01% PNH population
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematopoietic stem cell disorder characterized by a somatic mutation of the PIG-A gene leading to a deficiency of the cell membrane anchor glycosylphosphatidylinositol (GPI) and a deficiency of GPI linked proteins. PNH has three distinct clinical features; complement-mediated and primarily intravascular hemolysis, thrombotic tendency and underlying bone marrow failure. The International PNH Interest Group lists three main categories of presentation: classic PNH with hemolytic and thrombotic episodes, PNH in the context of other primary disorders and subclinical PNH. Deficiency in the GPI-anchor membrane protein CD59 (membrane inhibitor of reactive lysis) is used to identify PNH red blood cells (RBC) with identification of types I, II and III (III = totally lacking CD59, II = partially deficient, I = normal, CD59+).
A novel reagent, fluorescent aerolysin (FLAER) binds specifically to GPI-anchors and is used to evaluate WBC PNH clones. PNH populations will have no reactivity with the FLAER reagent. Lineage specific (CD15, CD33) monoclonal antibodies will be incorporated into gating algorithm, in addition to GPI-anchor linked proteins CD24 and CD14 for the WBC evaluation to increase specificity and sensitivity.
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