Red Blood Cells vs. White Blood Cells: What's the Difference?
Read the comparison below, or explore it visually. Create a visual lesson comparing red blood cells and white blood cells using available credits or plan allowance.
Red blood cells carry oxygen from the lungs to the body's tissues, while white blood cells defend the body against infection. Red cells are packed with the iron-rich protein haemoglobin and, in mammals, lose their nucleus to make room for it. White cells keep their nucleus, come in several types and are far fewer, with hundreds of red cells for every white cell.
At a glance
| Red Blood Cells | White Blood Cells | |
|---|---|---|
| Main job | Carry oxygen and some carbon dioxide | Fight germs and clear damaged cells |
| Nucleus | None in mature human red cells | Present; shape varies by type |
| Shape and colour | Red, biconcave disc about 7-8 micrometres | Colourless, irregular, mostly larger |
| Normal count | Roughly 4-6 million per microlitre of blood | Roughly 4,000-11,000 per microlitre |
| Lifespan | About 120 days | Hours to days; some memory cells for years |
Which should you use?
Red blood cells matter whenever oxygen delivery is the question, such as anaemia from iron deficiency, common in India, where too little haemoglobin leaves a person tired and breathless.
White blood cells matter whenever the body is fighting an invader, for example neutrophils gathering at an infected cut to form pus, or lymphocytes making antibodies after a vaccine.