ABSTRACT
This chapter provides some of the necessary underpinning knowledge in the physiological process and outlines the correct procedure to achieve accurate sampling. When a blood sample is analysed in laboratory, the levels of various substances that are present in the fluid part of the blood are measured. Full blood count (FBC) identifies the different types of white blood cells. The FBC is a haematological test, and may be done for several reasons, some of which are: hypertension; heart disease; diabetes; cancer; and so on. The erythrocyte sedimentation rate can indicate if there is any inflammation going on in the body. It will also be influenced by age and gender. Kidney function tests are performed to measure the levels of urea, creatinine and electrolytes, including sodium, potassium, chloride and bicarbonate. Thyroid function tests are done to diagnose thyroid disorders and to monitor people who have an underactive thyroid gland and who take thyroid replacement medication.
