Certified Dialysis Nurse Practice Test 2025 - Free Dialysis Nurse Practice Questions and Study Guide

The primary action of erythropoietin is to stimulate erythrocyte production. Erythropoietin is a hormone primarily produced in the kidneys in response to low oxygen levels in the blood. When the body detects these low levels, erythropoietin is released into the bloodstream and signals the bone marrow to increase the production of red blood cells (erythrocytes). This process is crucial in maintaining adequate oxygenation of body tissues, as red blood cells carry oxygen from the lungs to the rest of the body.

While other options describe functions that different hormones or substances perform, they are not related to the primary action of erythropoietin. For example, fluid retention is more closely associated with hormones like aldosterone and antidiuretic hormone (ADH), blood pressure regulation involves a variety of mechanisms including the renin-angiotensin system, and calcium absorption is influenced by hormones such as parathyroid hormone and vitamin D. Therefore, the role of erythropoietin is distinctly focused on enhancing red blood cell production to address oxygen demands.