Alternative Names full blood count, complete blood count
Definition A FBC, also called a full blood count, is a screening test used to diagnose and manage many diseases. A FBC measures the status of important features of the blood, including the:
number of red blood cells (RBCs)
number of white blood cells (WBCs)
number of platelets
total amount of haemoglobin in the blood
percentage of blood composed of cells, or haematocrit
mean corpuscular haemoglobin (MCH)
mean corpuscular haemoglobin concentration (MCHC)
mean corpuscular volume (MCV)
Who is a candidate for the test? A FBC is a part of routine blood testing done with physical examinations. It is also used to help diagnose many disorders, including problems with a person's blood, heart, kidney and nutritional status.
How is the test performed? A blood sample is taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube, or "tourniquet," is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow through them. A fine needle is gently inserted into a vein, and the tourniquet is removed. Blood flows from the vein through the needle, and is collected in a syringe or vial. After the needle is withdrawn, the puncture site is covered with a bandage for a short time to prevent bleeding.
What is involved in preparation for the test? A person should request specific instructions from his or her doctor.
What do the test results mean? Normal values are:
RBC (value changes with altitude): Male, 4.7 - 6.1 million cells/uL (cells per micro litre); female, 4.2 - 5.4 million cells/uL (cells per micro litre)
WBC: 4.0 - 11.0 thousand cells/uL (cells per micro litre)
haematocrit (varies with altitude): Male, 40.7-50.3%; female, 36.1-44.3%
eclampsia. Eclampsia is a serious condition involving high blood pressure, protein in the urine and swelling of the face and hands during pregnancy. It can lead to seizures and coma.
erythrocytosis, or an abnormal rise in the number of red blood cells.
polycythemia vera, or an increase in the cell mass or red blood cell levels in the blood.
rheumatoid arthritis, a long-term disease in which the connective tissue is destroyed
Low haemoglobin values may indicate:
anaemia
blood loss
Author: David T. Moran, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
