Platelet size for distinguishing between inherited thrombocytopenias and immune thrombocytopenia: a multicentric, real life study

• Published in: British journal of haematology Vol. 162; no. 1; pp. 112 - 119
• Main Authors: Noris, Patrizia, Klersy, Catherine, Gresele, Paolo, Giona, Fiorina, Giordano, Paola, Minuz, Pietro, Loffredo, Giuseppe, Pecci, Alessandro, Melazzini, Federica, Civaschi, Elisa, Mezzasoma, Annamaria, Piedimonte, Monica, Semeraro, Fabrizio, Veneri, Dino, Menna, Francesco, Ciardelli, Laura, Balduini, Carlo L.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01.07.2013; Blackwell Publishing Ltd
• Subjects: Adolescent; Adult; Aged; Biological and medical sciences; Blood Platelets - cytology; Cell Size; Diagnosis, Differential; Female; Hematologic and hematopoietic diseases; Humans; immune thrombocytopenia; inherited thrombocytopenias; Male; Medical sciences; Middle Aged; Platelet Count; platelet diameter; Platelet diseases and coagulopathies; platelet size; platelet volume; Platelets, Haemostasis and Thrombosis; Purpura, Thrombocytopenic, Idiopathic - blood; Purpura, Thrombocytopenic, Idiopathic - diagnosis; Reference Values; Sensitivity and Specificity; Thrombocytopenia - blood; Thrombocytopenia - diagnosis; Thrombocytopenia - genetics; Tumors; Young Adult; Thrombocytopenia; platelet diameter; Hematology; Multicenter study; immune thrombocytopenia; Hemopathy; Hereditary; platelet size; platelet volume; Platelet; Cancerology; inherited thrombocytopenias; Cell volume; Diameter
• ISSN: 0007-1048; 1365-2141; 1365-2141
• DOI: 10.1111/bjh.12349

Summary The most frequent forms of inherited thrombocytopenia (IT) are characterized by platelet size abnormalities and it has been suggested that this parameter is useful for their differentiation from immune thrombocytopenia (ITP). Recently, a monocentric study identified cut‐off values for mean platelet volume (MPV) and mean platelet diameter (MPD) with good diagnostic accuracy in this respect. To validate these cut‐off values in a different and larger case series of patients, we enrolled 130 subjects with ITP and 113 with IT in six different centres. The platelet count and MPV was each measured by the instrument routinely used in each institution. In some centres, platelet count was also measured by optical microscopy. MPD was evaluated centrally by image analysis of peripheral blood films. The previously identified cut‐off value for MPV had 91% specificity in distinguishing ITP from inherited macrothrombocytopenias (mono and biallelic Bernard‐Soulier, MYH9‐related disease), while its sensitivity was greatly variable depending on the instrument used. With an appropriate instrument, specificity was 83%. The diagnostic accuracy of MPD was lower than that obtained with MPV. We concluded that MPV is a useful parameter for differentiating ITP from IT provided that it is measured by appropriate cell counters.