Normal range: Above 4200000 cells/µL (higher is better)
The RBC count measures how many red blood cells are in a volume of blood. Red cells carry oxygen from your lungs to every tissue in your body. Low counts indicate anemia, which causes fatigue, weakness, and shortness of breath. High counts may signal dehydration, lung disease, or a bone marrow condition. RBC count is always interpreted alongside hemoglobin and hematocrit for the full picture.
RBC isn't sold on its own. It comes in a complete blood count (CBC), about $35. A fuller workup adds Vitamin D ($75), hs-CRP ($69), ApoB ($50), and ApoA1 ($50). You can test RBC and 100 other biomarkers for $190 as part of an Empirical membership.
Empirical is FSA/HSA eligible, so you can pay with pre-tax dollars. Fast for 8-12 hours beforehand for the most accurate lipid and metabolic results, and expect results in days rather than weeks.
RBC count measures the number of red blood cells, which carry oxygen from the lungs to body tissues.
Red Blood Cell Count stays relatively flat across adult ages (correlation with age, r = -0.05). Most of the spread in the chart below comes from differences between people rather than from age.
A normal RBC is Above 4200000 cells/µL. Higher is better.
Low RBC count (anemia) is most often caused by iron deficiency, especially common in women of reproductive age, vegetarians, and frequent blood donors. Vitamin B12 or folate deficiency, chronic kidney disease, and chronic inflammation also reduce red cell production.
Bone marrow disorders, heavy bleeding (menstrual or gastrointestinal), and certain medications (chemotherapy, some antibiotics) can lower the count. High RBC counts are usually caused by dehydration, smoking, or living at high altitude. Polycythemia vera (a rare bone marrow condition) causes persistently high counts.
Eating a diet rich in iron, B12, and folate supports healthy red cell production. If you have heavy periods or donate blood frequently, monitoring your RBC count and iron levels is especially important. Quitting smoking can help normalize an elevated count. Erythropoietin (EPO), used for chronic kidney disease-related anemia, directly stimulates red cell production.
RBC is most highly correlated with Absolute Neutrophils and White Blood Cell Count. Here are the top biomarkers correlated with RBC, based on 500,000 tests done by Empirical Health.
The percentage shows how strongly two biomarkers move together. A higher number means the relationship is stronger. Green = rises and falls together. Orange = one rises as the other falls.
RBC is drawn at 2,200+ Quest and BioReference patient service centers across the US, so there's usually one within a short drive. Browse the full directory to find the one closest to you.
Test your Red Blood Cell Count and 100+ other biomarkers in a single blood draw.
