A full blood count (FBC) test helps identify various medical conditions, including blood cancers and immune system disorders.
By measuring components such as red blood cells, which contain oxygen-carrying protein, and platelets, essential for blood to clot, healthcare providers can assess overall health and detect abnormalities.
By understanding your FBC results, you can take proactive steps for timely interventions and better management of any potential health concerns.
What is a full blood count blood test?
A full blood count, also known as a Complete Blood Count (CBC), is a routine blood test that assesses the number and size of red blood cells, white blood cells, and platelets. It is a broad screening test to check on overall health conditions and detect several disorders such as anaemia, infection, and leukaemia.
Blood is an essential part of living cells in our body to carry nutrients, oxygen, hormones, antibodies, and heat to different body tissues.
It consists of three primary components: red blood cells, white blood cells, and platelets, all suspended in a fluid called plasma.
Red blood cells contain haemoglobin, which carries oxygen to tissues throughout the body. White blood cells protect our body against harmful foreign substances such as bacteria, viruses, fungi, and parasites. Platelets help in the blood clotting process.
What is being tested in a full blood count?
Red blood cells
The full blood count provides a detailed analysis of your red blood cells, including several key components:
Haemoglobin (Hb):
An iron-containing protein that carries oxygen throughout the body.
Red blood cell (RBC) count:
Measures the total number of red blood cells present in a given volume of your blood.
Mean corpuscular volume (MCV):
Measures the average size of your RBCs.
Mean corpuscular haemoglobin (MCH):
Measures the average amount of haemoglobin per RBC.
Mean corpuscular haemoglobin concentration (MCHC):
Measures the average haemoglobin concentration per RBC.
Abnormalities in these parameters may indicate conditions such as anaemia, iron deficiency anaemia, or other blood disorders.
White blood cells
WBC in FBC is the actual amount of white blood cells per volume of blood. It measures various components of WBC in the FBC test.
Additionally, a white blood cell differential provides a breakdown of different types of WBCs, including:
Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes
Why would I need a full blood count test?
Healthcare providers often use FBC for several reasons, which include:
General health assessment:
An FBC provides a comprehensive overview of your overall health and helps detect any potential abnormalities.
Diagnosis of blood disorder:
The FBC test diagnoses certain conditions such as anaemia, infection, leukaemia, and blood clotting disorders.
Monitor treatment:
The FBC test monitors the effectiveness of treatment for blood disorders such as anaemia, leukaemia, and blood clotting disorders.
Monitor side effects of medications:
Certain medications can impact blood cell counts. The FBC test can help monitor these potential side effects.
Preoperative screening:
The FBC test is often required before surgery to ensure that the patient has an optimal blood supply for the procedure.
To take charge of your health, book an appointment with Thomson Medical to meet our medical specialists and discuss a personalised treatment plan.
How do you prepare for this test?
In most cases, no special preparation is needed for the FBC test. However, if your healthcare provider plans to run some extra tests, they might ask you to fast beforehand. There may also be instances where you’ll need to pause certain medications before the test.
It is advisable to consult your healthcare provider for specific instructions before your blood draw.
Test Procedure
The FBC test is a simple blood withdrawal procedure.
During the procedure, you are asked to sit or lie down.
A tourniquet is put around your arm and tightened to increase the blood volume in your vein. Your healthcare provider (e.g., nurse or phlebotomist) may ask you to clench your fist to increase the blood volume in your vein.
The injection site is wiped with alcohol to reduce the risk of infection.
Your healthcare provider will insert a needle into your vein and draw a small amount of blood, which is collected in a syringe or vial. You may experience slight pain or discomfort during the procedure.
After the blood is collected, your healthcare provider may ask you to press gauze or cotton wool against the injection site to minimise bleeding. The site will then be covered with an adhesive bandage. You may experience a small bruise at the injection site for a day or two.
Understanding your results
Each type of blood cell in your body has a specific normal range in terms of both quantity and ratio.
When you receive your blood test results, your healthcare provider will compare them to standard charts that show the typical ranges for each blood cell type. If any of your blood cell levels are above or below the normal range, it could indicate an underlying issue.
Some potential abnormalities in your blood sample could include:
Red blood cells and haemoglobin:
Low levels can mean iron deficiency, blood loss, or chronic diseases like kidney issues.
High levels might show how the body adapts to high altitudes. They may also signal chronic lung disease or indicate polycythaemia vera.
White blood cells:
A low count may mean you have a viral infection, bone marrow problems, or exposure to radiation or chemotherapy.
High levels can indicate bacterial infections, inflammatory diseases, or bone marrow disorders.
Platelets:
A low platelet count may be associated with viral infections, bone marrow disorders, or autoimmune diseases.
High platelet levels may suggest bone marrow disorders or inflammatory conditions.
FAQ
What is the FBC blood test for?
The FBC blood test is a common routine blood test that is used by healthcare providers to detect a wide range of illnesses, infections, and diseases. This blood test provides important information on different blood cells, such as red blood cells, white blood cells, and platelets. Results above or below the normal range in the blood cells may indicate certain disorders.
Does the FBC blood test require fasting?
No, the FBC blood test does not require fasting, as it does not affect the blood cells. However, you should discuss this matter with your healthcare provider because they may order additional tests that require fasting, such as a lipid profile and fasting glucose level.
Can I drink water before the FBC test?
Yes, you can drink water before the FBC test, as water does not affect the blood cells.
What is the normal FBC range?
The normal values for each of these three main blood cells are
Haemoglobin: The normal adult range in Singapore is 13.1-16.8 g/dL for men and 11.5-14.9 g/dL for women.
White cell count: The normal adult range in Singapore is 4.3-10.4 x 109/L.
Platelet count: The typical range in Singapore for adults is 150-410 x 109/L.
What problems can a full blood count detect?
The complete blood count test detects various abnormalities, such as
Too few red blood cells (anaemia):
Anaemia may also have less haemoglobin than normal in each red blood cell. A common cause of anaemia is a lack of iron (iron deficiency anaemia). Iron deficiency anaemia can be due to prolonged menses in females or sudden heavy blood loss in surgery or an accident.
Too many red blood cells (polycythaemia):
The causes of polycythaemia are physiological changes in response to high altitudes, smoking, chronic lung disease, and polycythaemia vera.
Too few white blood cells (leucopenia):
Depending on the type of white cell that is reduced, it can be called neutropenia, lymphopenia, or eosinophilia. There are various causes that lead to leukopenia, such as viral infection, bone marrow disorder, medication, and autoimmune disorder.
Too many white blood cells (leukocytosis):
Depending on the type of white cell that is increased, it can be called neutrophilia, lymphocytosis, or eosinophilia. There are various causes that lead to leukocytosis, such as infection, allergy, and leukaemia.
Too few platelets (thrombocytopenia):
Thrombocytopenia may be due to autoimmune disorder, viral infection, medications, and idiopathic (unknown cause).
Too many platelets (thrombocytosis):
A common cause of thrombocytosis is bone marrow disorder.
What cancers can a full blood count detect?
The FBC can help detect certain blood and immune system cancers, such as leukaemia and lymphoma. However, it is not effective for identifying solid organ cancers like lung, breast, or colon cancer. Instead, it provides valuable information on how your body is responding to treatment and whether the cancer has spread to your bone marrow.
The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations based on your medical conditions, request an appointment with Thomson Medical.
For more information, contact us:
Thomson Specialists Paragon (Health Screening)
- Mon - Fri: 8.30am - 5.30pm
- Sat: 8.30am - 12.30pm
Call: 6735 0300
Request a Health Screening