systemic disease

The full blood count (FBC) is perhaps the single most common investigation performed in medical patients. It has the potential, when interpreted carefully and in relation to the clinical history, to provide very useful information to assist in diagnosis and management. Clinicians are often alerted to the presence of a primary haematological disorder by abnormalities in the FBC. For the purpose of this review these diseases will not be discussed in detail but the reader will be alerted to pointers which might indicate primary blood disorders throughout the text.