Units	varies by component (g/dL, %, cells per microlitre)
Standard range	laboratory-specific (ranges vary by lab)
red_cells	haemoglobin, haematocrit and RBC count — low values may indicate anaemia, which has many causes; a clinician works out which
white_cells	a high count may signal infection or a reaction to a medicine; a low count has several possible causes and needs clinical interpretation
platelets	platelets help blood clot — flagged values need clinical interpretation, not self-assessment
differential	a CBC with differential counts each of the five types of white blood cell separately, because they do different jobs
abnormal	an abnormal value does not always mean a condition that needs treatment — diet, activity, medicines, a menstrual period and not drinking enough water can affect results
Never	do not start iron or any supplement on a CBC alone — iron can be harmful if you get too much
Frequency	as your clinician directs; a CBC is often part of a routine checkup
If flagged	an abnormal value does not always mean a condition that needs treatment; talk with your clinician about what it means
Preparation	usually none — no fasting is needed for a CBC alone, though other tests on the same sample may require it
Iron context	low haemoglobin has several possible causes, including iron, vitamin B12 or folate deficiency — ask your clinician which one before assuming iron deficiency

CBC — What the Full Blood Count Shows — 60-Second Protocol

The protocol