RBC count

Alternative names:

erythrocyte count; red blood cell count

What the risks are:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations:

The RBC count may be decreased during pregnancy because of an increase in body fluids.

The RBC will increase over a period of several weeks after moving to a higher altitude.

Dehydration increases the RBC count.

Drugs that can increase the RBC count include gentamicin and methyldopa. Drugs that can decrease the RBC count include chloramphenicol, hydantoins and quinidine.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.