The WHO diagnostic criteria for polycythemia vera—role of red cell mass versus hemoglobin/hematocrit level and morphology

• Published in: Annals of hematology 2018-09, Vol.97 (9), p.1581-1590
• Main Authors: Jakovic, Ljubomir, Gotic, Mirjana, Gisslinger, Heinz, Soldatovic, Ivan, Sefer, Dijana, Tirnanic, Mila, Lekovic, Danijela, Jovanovic, Maja Perunicic, Schalling, Martin, Gisslinger, Bettina, Beham-Schmid, Christine, Simonitsch-Klupp, Ingrid, Thiele, Jürgen
• Format: Article
• Language: English
• Subjects: Blood cancer; Hematology; Medical diagnosis; Medicine; Medicine & Public Health; Morphology; Oncology; Original Article
• ISSN: 0939-5555; 1432-0584
• DOI: 10.1007/s00277-018-3344-3

Regarding diagnosis of polycythemia vera (PV), discussion persists about hemoglobin (Hb) and/or hematocrit (Hct) threshold values as surrogate markers for red cell mass (RCM) and the diagnostic impact of bone marrow (BM) morphology. We performed a retrospective study on 290 patients with PV (151 males, 139 females; median age 65 years) presenting with characteristic BM features (initial biopsies, centralized evaluation) and endogenous erythroid colony (EEC) formations. This cohort included (1) a group of 229 patients when following the 2008 versus 256 patients diagnosed according to the 2016 World Health Organization (WHO) guidelines, all presented with increased RCM; (2) masked PV patients with low Hb ( n  = 143)/Hct ( n  = 45) recruited from the 2008 WHO cohort; (3) a cohort of 17 PV patients with elevated diagnostic Hb/Hct levels but low RCM; and (4) nine PV patients with increased RCM, opposing low Hb/Hct values. All patients were treated according to current PV guidelines (phlebotomies 87%, hydroxyurea 79%, and acetylsalicylic acid 87%). Applying the 2016 WHO criteria significantly increased concordance between RCM and Hb values compared with the 2008 WHO criteria (90 vs. 43% in males and 83 vs. 64% in females). Further analysis of the WHO 2016 PV cohort revealed that increased RCM is associated with increased Hb/Hct (93.8/94.6%). Our study supports and extends the diagnostic impact of the 2016 revised WHO classification for PV by highlighting the importance of characteristic BM findings and implies that Hb/Hct threshold values may be used as surrogate markers for RCM measurements.