With absolute erythrocytosis, serum EPO determinations have been recommended to differentiate primary from secondary causes. Unfortunately, considerable overlap exists in EPO activity among normal animals, animals with primary erythrocytosis, and animals with secondary erythrocytosis. Furthermore, current availability of validated EPO assays for companion animals is limited. Routine examination of bone marrow is not useful to distinguish primary from secondary erythrocytosis because both conditions show erythroid hyperplasia. As a result, primary erythrocytosis usually is diagnosed by eliminating secondary causes. | With absolute erythrocytosis, serum EPO determinations have been recommended to differentiate primary from secondary causes. Unfortunately, considerable overlap exists in EPO activity among normal animals, animals with primary erythrocytosis, and animals with secondary erythrocytosis. Furthermore, current availability of validated EPO assays for companion animals is limited. Routine examination of bone marrow is not useful to distinguish primary from secondary erythrocytosis because both conditions show erythroid hyperplasia. As a result, primary erythrocytosis usually is diagnosed by eliminating secondary causes. |