Hydroxyurea-induced cyclic variations of platelet count and serum thrombopoietin concentration (TPO) in a patient with polycythemia vera.

The reference range for TPO is 11 to 70 pg/mL, and for serum EPO concentration it is 4 to 24 pg/mL. No remarkable variations were noted in hematocrit (Hct), white blood cell count (WBC), or EPO concentration. Alpha INF, α-interferon.