Health guide
Complete Blood Count (CBC): what the test means
The Complete Blood Count, or CBC, is the most commonly ordered blood test. It counts and measures the three main types of cells in your blood (red cells, white cells, and platelets) and is a broad first screen for anaemia, infection, and problems with clotting. It is quick, inexpensive, and part of almost every routine health checkup.
Reviewed by Dr. Vishal Singh, Lab DirectorUpdated
When a CBC is useful
- Tiredness, weakness, or suspected anaemia
- Fever or a suspected infection
- Easy bruising or unusual bleeding
- Before surgery or a procedure
- As part of a routine annual checkup
- To monitor a known condition or its treatment
What a CBC measures
Haemoglobin and red blood cell counts show whether you are anaemic. White blood cells reflect your immune response. They often rise with infection. Platelets are involved in clotting, so a low count can mean a higher bleeding risk. The report also includes indices such as MCV (red cell size), which help point to the cause of an anaemia.
What high or low values can mean
A low haemoglobin suggests anaemia, which has many causes from iron or B12 deficiency to blood loss. A high white cell count often points to infection or inflammation. A low platelet count may need attention if you bruise or bleed easily. A CBC narrows down the possibilities; your doctor reads the whole pattern together and may order follow-up tests.
This guide is for general information and is not a diagnosis. Always discuss your symptoms and results with a doctor.
Tests that help
Recommended panel
ImmuneShield
7 biomarkers in one panel
Frequently asked questions
Do I need to fast for a CBC?
No. A Complete Blood Count does not require fasting and can be done at any time. If it is bundled with a lipid or sugar test, follow the fasting advice for those.
What does a CBC test detect?
It screens for anaemia, infection, inflammation, and clotting problems by measuring your red cells, white cells, haemoglobin, and platelets. It is a starting point, not a final diagnosis.
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