[1400] Mean Platelet Volume Aids in the Differential Diagnosis of Chronic Myeloproliferative Neoplasms

John L Frater, Charles S Eby. Washington University School of Medicine, St Louis, MO

Background: Platelet parameters are described as being of potential use in the differential diagnosis of chronic myeloproliferative neoplasms (MPNs), though evidence based support for this assertion is relatively lacking. In particular, the role of mean platelet volume (MPV), which is routinely generated by automated blood analyzers, is ambiguous.
Design: We selected 153 patients with MPNs diagnosed at a tertiary care medical center by bone marrow biopsy and ancillary testing, including 55 patients with essential thrombocythemia (ET) (38F, 17M, mean age 64 years), 41 with primary myelofibrosis (PMF) (11F, 30M, mean age 61 years), 9 patients with polycythemia vera (6F, 3M, mean age 62 years), and 48 patients with chronic myelogenous leukemia, including 31 chronic phase (14F, 17M, mean age 53 years), 4 accelerated phase (3F, 1M, mean age 45 years), and 13 blast phase (7M, 6F, mean age 56 years) individuals. Cell analyzers from Beckman-Coulter (Brea, CA) were used to measure platelet counts and MPVs for all patients. Student's t-test was used to analyze the calculated averages.
Results: Average platelet counts exceded the normal range in ET (737k) and PV (509k) and were within the normal range for PMF (188k) and CML (329k). The average MPVs for all groups were within the normal range.

Diagnosis	Avg plt count (k)	Avg MPV (fL)	Avg MPV (cases w/ increased plts)
ET	737	7.9	7.7
PMF	188	8.0	8.9
PV	509	8.6	9.1
CML	329	8.9	9.4

Statistically significant differences in platelet count were noted between ET and PMF (p=9x10-¹⁰), ET and CML (p=9x10^-6), PMF and PV (p=0.0002), PMF and CML (p=0.001), and PV and CML (p=0.01). In addition, there were statistically significant differences in MPV between ET and CML (p=0.001) and PMF and CML (p=0.007). In cases with increased platelets, there were statistically significant differences in MPV between ET and PV (p=0.003) and ET and CMF (p=0.02). There were no statistically significant differences in platelet count or MPV between Jak2 mutated versus germline cases.
Conclusions: 1) In contrast to the reported literature, MPV is not uniformly elevated or decreased in MPNs. 2) MPV differs significantly between CML and 2 other classes of MPN (ET and PMF). 3) In patients with thrombocytosis a low MPV aids in the distinction of ET from PV and PMF. 4) Differences in MPV are unrelated to Jak2 mutational status.
Category: Hematopathology

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 222, Wednesday Morning