A CBC - complete blood count - measures your red blood cells, white blood cells, and platelets: the workhorse panel of medicine.
Low red cells signal anemia, white-cell shifts point toward infection or immune problems, and platelets reflect clotting. It screens at physicals and investigates fatigue, fever, bruising, or weakness, with no fasting needed. One slightly out-of-range number is a conversation, not a crisis.
What to do
Common questions
What is a CBC blood test?
A CBC - complete blood count - is the workhorse panel of medicine, measuring the cells that make up your blood. Per MedlinePlus, it counts red blood cells (which carry oxygen - low numbers signal anemia), white blood cells (which fight infection - high or low counts point toward infection, inflammation, or immune problems), and platelets (which clot your blood), plus related measures like hemoglobin and hematocrit. A "CBC with differential" adds the breakdown of the five white-cell types for finer diagnosis. Doctors order it for everything from routine physicals to investigating fatigue, fever, bruising, or weakness, and no fasting is needed. One number slightly out of range is usually a conversation, not a crisis - your doctor reads the pattern against your symptoms and history. Pymander, a free AI doctor available 24/7 by text, can help you understand your specific results when they post.