Overview
A complete blood count measures the numbers of red blood cells, haemoglobin, white blood cells and platelets. It is one of the most commonly ordered tests and gives a broad picture of overall health.
Why it's done
It is ordered for routine check-ups, when anaemia, infection or inflammation is suspected, and to monitor treatment.
How to prepare
No special preparation is usually needed. If other tests are taken from the same sample (e.g. glucose), fasting may be required — check with your doctor.
What to expect
Blood is drawn from a vein and the procedure takes a few minutes. You may feel mild discomfort or get a small bruise at the puncture site.
Understanding the results
Low haemoglobin suggests anaemia; raised white cells suggest infection or inflammation; abnormal platelets point to clotting issues. Results should always be interpreted by a doctor alongside the clinical picture.