Absolute Leucocyte Count
Understanding Absolute Leucocyte Count
What is Absolute Leucocyte Count?
The Absolute Leucocyte Count test measures the total number of white blood cells (WBCs) or leucocytes in a given volume of blood. This test is often a part of a complete blood count (CBC) test and helps diagnose and monitor conditions such as infections, inflammation, immune disorders, and certain types of blood cancers.
WBCs play an important role in defending the body against foreign invaders such as pathogens, allergens etc and help maintain overall immune function. WBCs are of five main types namely, neutrophils, lymphocytes, monocytes, basophils and eosinophils. Each type has a specific function in the immune response. Neutrophils are the most abundant cells and crucial for fighting against bacterial infections. Lymphocytes which include B and T cells, mandatory for acquired immunity including the production of antibodies and the destruction of infected cells. Monocytes help find and destroy germs (bacteria, virus, fungi, protozoans etc.) and eliminate infected cells. Eosinophils and basophils are involved in the defense against parasites and allergic reactions.
The Absolute Leucocyte Count test is a fundamental test used to assess the immune system’s health and the body’s ability to fight off infections. It is often done as part of complete blood count (CBC), a test often used as a general health check, or it may be done in follow-up to abnormal CBC test results. Also, this test can be done on a regular basis if you are being treated or monitored for a WBC-related disease.
The Absolute Leucocyte Count test is particularly important when you have general signs and symptoms of an infection or inflammation, such as fever, chills, bodyache, headache or other specific symptoms related to an infection or inflammation in the body which could suggest a blood, bone marrow or an autoimmune disorder. Also, the Absolute Leucocyte Count test helps monitor your response to medical treatments that can affect the immune system, including chemotherapy, or other immunosuppressive therapies known to affect the number of leucocytes.
No special preparation is needed for this test. However, inform your doctor about any medications or supplements you are taking, as some of them may affect your test results. Your doctor might ask you to temporarily discontinue certain medications before the test.
Test result ranges can vary slightly across laboratories. Never self-medicate at home solely based on these results and always consult your doctor for proper understanding of your test results. The test results will help your doctor determine your medical condition, make recommendations for lifestyle modifications such as diet and exercise, decide whether or not medication will be required to manage your condition and formulate your overall treatment plan.
What is Absolute Leucocyte Count used for?
The Absolute Leucocyte Count test is done:
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To identify bacterial, viral, fungal, or parasitic infections
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To assess the body’s defense mechanism and detect immune system disorders
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To detect white blood cell disorders such as leukemia, lymphoma, and other bone marrow diseases
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To assess inflammatory conditions such as arthritis or allergies
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To detect disorders associated with leukopenia (low number of WBCs) and leukocytosis (high number of WBCs)
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To monitor treatments affecting the number of WBCs, such as chemotherapy or radiotherapy
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Often as part of a routine health checkup or complete blood count(CBC) test to monitor your overall health
What does Absolute Leucocyte Count measure?
Contains 5 testsThe Absolute Leucocyte Count test measures the total number of white blood cells (leucocytes) in the given volume of blood. It examines different types of white blood cells such as neutrophils, lymphocytes, monocytes, basophils and eosinophils. These cells tell about the status of the immune system and its ability to fight off infections and other conditions like inflammation, allergies, bone marrow disorders etc.
Absolute Lymphocyte Count
An Absolute Lymphocyte Count test measures the total number of lymphocytes in the blood. Lymphocytes are a type of white blood cells that play an important role in your immune system and help your body fight disease and infection. There are two main types of lymphocytes:
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T lymphocytes (T cells): T cells control your body’s immune system response and directly attack and kill infected cells and tumor cells.
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B lymphocytes (B cells): B cells make antibodies. Antibodies are proteins that target viruses, bacteria, and other foreign pathogens.
Lymphocytes help your immune system remember every antigen (a foreign substance) it comes in contact with. After an encounter, some lymphocytes turn into memory cells. When these memory cells run into an antigen again, they recognize it and quickly respond. It is also the reason why getting vaccinated helps prevent certain diseases.
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Absolute Eosinophil Count
An Absolute Eosinophil Count test measures the number of eosinophils in the blood and provides important information about the functioning of the immune system. Eosinophils originate from bone marrow and have a lifespan of 8-18 hours. These cells are involved in fighting certain types of infections and responding to allergic reactions in the body. Other functions of these cells include movement to the inflammation areas, trapping substances, killing cells, and bactericidal and antiparasitic activities. They also help in the treatment of immediate allergic reactions and modulation of inflammatory responses. By measuring the number of eosinophils in the blood, this test provides important information about the functioning of the immune system.
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Absolute Neutrophil Count
An Absolute Neutrophil Count test measures the percentage of neutrophils per microliter of blood. Neutrophils are a type of WBC and play an integral part in the body's immune system. They help fight off bacterial infections in the body by identifying and destroying foreign invaders, such as disease-causing microorganisms.
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Absolute Basophil Count
An Absolute Basophil Count test measures the total number of basophils in the blood. Basophils are small, spherically-shaped cells that originate from bone marrow and make up almost 1% of the total white blood cells in the body. They attack a foreign substance and release proteins like histamine and heparin to destroy harmful substances, such as allergens, pathogens, or parasites. Histamine helps widen the blood vessels and make space for more immune cells to come to the site of infection or injury, whereas heparin acts as a blood-thinning agent and helps to avoid blood clotting at that site.
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Absolute Monocyte Count
An Absolute Monocyte Count test measures the total number of monocytes in the blood. Monocytes are a type of WBC that originate from bone marrow and travel to different tissues via the blood. Once they are inside the tissue, these cells get converted to macrophages (a type of cell that digest harmful substances). Monocytes are the second line of defense mechanism of the human body after neutrophils. These cells are also responsible for the removal of injured or dead cells, microorganisms, and other insoluble particles from the blood.
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Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Absolute Leucocyte Count
Frequently Asked Questions about Absolute Leucocyte Count
Q. In what conditions a doctor may suggest the Absolute Leucocyte Count test?
Q. How is the Absolute Leucocyte Count test performed?
Q. Do I need to fast before taking the Absolute Leucocyte Count test?
Q. How often should I get the Absolute Leucocyte Count test done?
Q. What should I do if my Absolute Leucocyte Count test results are abnormal?
Q. What are the different types of leukocytes?
Q. What is leukocytosis?
Q. What is leukopenia?
References
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- What Are White Blood Cells? [Interent]. Rochester, NY: University of Rochester Medical Center; [Accessed 14 May 2024]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentID=35&ContentTypeID=160
- Shafi SM, Afsheen M, Reshi FA. Total leucocyte count, C-reactive protein and neutrophil count: diagnostic aid in acute appendicitis. Saudi J Gastroenterol. 2009 Apr;15(2):117-20. [Accessed 14 May 2024]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702981/
- Corre F, Lellouch J, Schwartz D. Smoking and leucocyte-counts. The Lancet. 1971;298(7725):632-634. [Accessed 14 May 2024]. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0140673671800715
- England JM, Bain BJ. Total and differential leucocyte count. Br J Haematol. 1976 May;33(1):1-7. [Accessed 14 May 2024]. Available from: https://pubmed.ncbi.nlm.nih.gov/1268083/
- A T Raftery, The value of the leucocyte count in the diagnosis of acute appendicitis, British Journal of Surgery, 1976 Feb;63(2):143–144. [Accessed 14 May 2024]. Available from: https://academic.oup.com/bjs/article-abstract/63/2/143/6192481
- Mank V, Azhar W, Brown K. Leukocytosis. [Updated 2024 Feb 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560882/
- Hamad H, Mangla A. Lymphocytosis. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549819/
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