European vs 2015-World Health Organization clinical molecular and pathological classification of myeloproliferative neoplasms

Table 3 Comparion of clinical and laboratory features between polycythemia vera study group defined polycythemia vera (group A) and inapparent polyctemia vara (group B)

Clinical feature	Group A PV	Group B IPV	P-value
No. of cases	85	18
Age (range)	61 (27-83)	52 (28-82)	NS
Sex male/female	56/42%	39/61%	NS
Splenomegaly	44 (52%)	15 (83%)	< 0.005
Leukocytes > 12 × 10/L	31 (36%)	5 (28%)	NS
Platelets > 500 × 10/L	40 (47%)	10 (56%)	NS
Red cell counts × 10/L: males	6.2 (4.9-7.4)	5.2 (4.7-5.9)	< 0.0002
Red cell mass males	48.2 (36-60)	43.3 (41-61)	NS
Red cell counts females	6 (4.2-7.3)	4.7 (3.7-5.5)	< 0.003
Red cell mass females	40.1 (32-59)	37.3 (34-46)	NS
Plasma volume PV vs IPV
Increase/theoretical norm (%)	10 (-11, 61)	36 (20, 98)	< 0.00001

Lamy et al[44]. Conclusion: inapparent polycythemia vara (IPV) is featured by normal values of haemoglobin, haematocrit and erythrocyte counts, in the absence of hypervolumic symptoms and in IPV red cell mass is increased related to the degree of increased spleen size. NS: Not significant.