Polycythemia vera laboratory tests
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Polycythemia vera Microchapters |
Diagnosis |
---|
Treatment |
Case Studies |
Polycythemia vera laboratory tests On the Web |
American Roentgen Ray Society Images of Polycythemia vera laboratory tests |
Risk calculators and risk factors for Polycythemia vera laboratory tests |
Please help WikiDoc by adding more content here. It's easy! Click here to learn about editing.
Overview
Laboratory Findings
Patients with polycythemia vera may often be asymptomatic. The diagnosis is often suspected on the basis of laboratory tests. Common findings include an elevated hemoglobin level or hematocrit, reflecting the increased number of red blood cells; the platelet count or white blood cell count may also be increased. Because polycythemia vera results from an essential increase in erythrocyte production, patients have a low erythropoietin (EPO) level.
In primary polycythemia, there may be 8 to 9 million and occasionally 11 million erythrocytes per cubic millimeter of blood (a normal range for adults is 4-6), and the hematocrit may be as high as 70 to 80%. In addition, the total blood volume sometimes increases to as much as twice normal. The entire vascular system can become markedly engorged with blood, and circulation times for blood throughout the body can increase up to twice the normal value. The increased numbers of erythrocytes can cause the viscosity of the blood to increase as much as five times normal. Capillaries can become plugged by the very viscous blood, and the flow of blood through the vessels tends to be extremely sluggish.