Elevated red blood cell counts may occur in response to dehydration, which decreases blood plasma levels, according to Mayo Clinic. Kidney, heart and bone marrow disease may also increase red blood cell production. This occurs in people who smoke, have sleep apnea or live in high altitude areas as well
Red blood cell counts are ordered as part of a complete blood count, according to the American Association for Clinical Chemistry. A physician may order these tests for a routine exam or if he suspects a condition that affects red blood cell production. Symptoms of elevated red blood cell counts include disturbed vision, headaches and a large spleen, according to the American Association for Clinical Chemistry.