Low White Blood Cell Count Tests

White Blood Cell Counts are an important indication of the state of immunity of the body. An increase in the white blood cells are generally indicative of an active attempt of the body to get rid of infections in the body, with different counts indicating about the type of i
Low White Blood Cell Count Tests
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White Blood Cell Counts are one of the routinely done tests in cases of all infections, allergies and other sicknesses. They are done to assess the resistance of the body to harmful micro-organisms. The most commonly done test is CBC or the Complete Blood Count. Understanding its basics may allay some of the anxiety associated with it.


Low White Blood Cell Count refers to a condition where the number of white blood cells in blood fall below the normal range of 4000 to 11000 cells per cubic micro litre.

White Blood Cells: An Introduction

Blood contains mainly three types of cells - red

blood cells, platelets and white blood cells. White blood cells include five different types of cells:

(i) Neutrophils
(ii) Eosinophils
(iii) Basophils
(iv) Lymphocytes
(v) Monocytes

The Neutrophils are the largest proportion, constituting around 40 to 70 % of all white blood cells in a normal person. The primary role of white blood cells in blood is to protect the body from infections by bacteria and other micro-organisms.

Tests to Detect Low White Blood Cells

The main test that detects a case of low white blood cells in the 'COMPLETE BLOOD COUNT'


This test is also known as FULL BLOOD COUNT (FBC) or FULL BLOOD EXAM (FBE). It provides a count of the total white blood cells in every micro litre of blood.

CBC is done in two ways:

(i) MANUAL BLOOD COUNT - In this count, a sample of blood is collected from the individual, which is mixed with a anticoagulant and taken to a laboratory, where a smear of blood is prepared on a glass slide and stained with a proper stain that affects only white blood cells so that under a microscope, when the slides is examined only the white blood cells will be visible. These white blood cells visible under each field are counted in a number of different microscopic fields and an

average of the number is the white blood cell count.

(ii) AUTOMATED CELL COUNT - Counting of white blood cells is usually done these days using an automated system. The machines used for this purpose are the Beckman Coulter LH series, Sysmex XE-2100, Siemens ADVIA 120 & 2120, and the Abbott Cell-Dyn series. The blood is kept on a rack in the analyzer machine. From there a small sample is automatically drawn through a capillary tube that is fixed with sensors that count the number of cells moving through it. This counting provides the cell count by way of FLOW CYTOMETRY.


The results or observations of a CBC may fall in to three categories:

- NORMAL : 4000 to 11000 cells / ul

- LOW WHITE BLOOD CELL COUNT : Less than 4000 cells / ul of blood. This primarily indicates a fall in neutrophil count or NEUTROPENIA, and is associated with increased vulnerability to infections.

- HIGH WHITE BLOOD CELL COUNT : More than 4000 cells / ul of blood. It usually happens in bacterial infections as a reaction of the body to fight that infection. However, it can also happen in case of blood cancers and certain other diseases.


To find out what is exact count of each of the white blood cells, a DIFFERENTIAL LEUCOCYTE COUNT (DLC) needs to be done. Most of the times, both CBC and DLC are undertaken together as part of lab investigations.

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