Urinary erythropoietin levels in normal, anaemic, polycythaemic, and uraemic subjects.

The erythropoietin content of 24 hour urine collections has been assayed in a number of clinical conditions and in five normal subjects Low erythropoietin levels were found in polycythaemia vera, anaemia associated with uraemia and rheumatoid arthritis. High levels were found in association with hypoxic polycythaemia and anaemia due to iron deficiency, blood loss and marrow hypoplasia. In addition significant quantities of erythropoietin were found in renal cyst fluid and in the isotonic extract of a uterine leiomyoma removed from patients with polycythaemia.