RESUMO
BACKGROUND: Polycythemia is a common medical problem, frequently acquired and reactive to secondary conditions. High-altitude-associated hypoxia contributes to the greater prevalence of polycythemia at altitude. Primary clonal polycythemia vera (PV), even though it is rare, requires a different therapeutic approach. Suspicion of PV usually drives the diagnostic workup of polycythemia. METHODS: In this retrospective lab record study, we collected all JAK2 tests requested over a three-year period. We analyzed requests that were made for the evaluation of polycythemia. Complete blood count (CBC) and imaging of the abdomen were collected. RESULTS: Out of 208 total requests, 136 were for the purpose of polycythemia evaluation. JAK2 mutation was positive (confirming the presence of PV) in 22 (16.7%) cases. PV patients have the usual demographics reported elsewhere. Additionally, PV patients exhibit distinct hemogram results featuring leukocytosis, thrombocytosis, and hypochromic microcytic red blood cells (RBCs) related to the associated iron deficiency. CONCLUSIONS: Many patients with polycythemia at altitude might be unnecessarily considered for an evaluation of PV, if hemoglobin/hematocrit is the sole deciding criterion. PV patients have a distinct CBC pattern that can be exploited to better select patients with polycythemia for further evaluation and thus reduce unnecessary workups.