What do all chronic myeloproliferative disorders share?

a. Philadelphia chromosome
b. Increased red cell mass
c. Increased blood cells; overlapping clinical and laboratory features
d. Serious thromboembolic complications

ANS: C
The chronic myeloproliferative disorders all have increased blood cells, although which one (or ones) varies depending on the condition. They also all have overlapping clinical features. The Philadelphia chromosome is only found in chronic myelogenous leukemia within this classification. Polycythemia vera uniquely has an increased red cell mass, and serious thromboembolic complications are primarily seen in essential thrombocythemia, although they also can be a complication of polycythemia vera when the patient is treated with phlebotomy only.