Red Blood Cell Count (RBC)

Why This Test Matters

Red blood cells (RBCs) carry oxygen from your lungs to the rest of your body and help remove carbon dioxide. A low RBC count may indicate anemia, bleeding, or other health issues, while a high count could signal conditions like dehydration or polycythemia vera. Your doctor may order this test to check for these problems or to monitor treatment effectiveness.

What to Expect Before the Test

You won’t need special preparation for this test. A simple blood draw from a vein in your arm is all that’s required. The process is quick and usually painless, though you may feel a slight pinch. If you’re nervous, let your healthcare provider know—they can offer tips to make it more comfortable.

What the Results Mean

Results are typically reported as the number of RBCs per microliter (µL) of blood. While reference ranges vary by lab and age, very low or very high counts may signal underlying health concerns that need further evaluation. Your doctor will interpret the results in the context of your medical history and symptoms.

Common Conditions Affecting RBC Count

Low RBC counts (anemia) can result from conditions like iron deficiency, chronic illness, or blood loss. High RBC counts may occur with conditions such as dehydration, lung disease, or certain cancers. Other factors, like pregnancy or certain medications, can also influence RBC levels.