Total WBC or White Blood Cell Count as a part of hemogram or CBC blood test

A white blood cell (WBC) count of less than 4 x 109/L indicates leukopenia.

A WBC count of more than 11 x 109/L indicates leukocytosis.

Decreased WBC count, leukopenia, is seen when supply is depleted by infection or treatment such as chemotherapy or radiation therapy, or when a hematopoietic stem cell abnormality does not allow normal growth/maturation within the bone marrow, such as myelodysplastic syndrome or leukemia. Leukopenia (decrease in WBC) is most often due to a lower number of neutrophils, referred to as neutropenia. Characteristically, the neutrophil count is less than 1.5 x 109/L. 

Elevated WBC, leukocytosis, is seen in response to infection, stress, inflammatory disorders (referred to as reactive leukocytosis), or abnormal production as in leukemia. An increased WBC count can be due to an individual cell component or a combination, depending on the cause. Malaise, chills, and fever, related to infection, are clinically seen in both leukopenia and neutrophilic leukocytosis.

Reactive leukocytosis can be classified on the basis of the white blood cell type affected. Criteria as well as common causes are below.

  • Neutrophilic leukocytosis occurs when neutrophils are greater than 7.5 x 109/L. Common causes are as follows:
  • Acute bacterial infections
  • Sterile inflammation/tissue necroses seen in myocardial infarction, burns, crush injuries.

Eosinophilic leukocytosis occurs when eosinophils are greater than 0.4 x 109/L. Common causes are as follows:

  • Allergic disorders such as asthma, hay fever 
  • Parasitic infections
  • Drug reactions

Basophilic leukocytosis occurs when basophils are greater than 0.1 x 109/L. Causes include rare allergic reactions (IgE mediated).

Monocytosis occurs when monocytes are greater than 0.8 x 109/L. Common causes include the following:

  • Chronic infections such as tuberculosis
  • Bacterial endocarditis
  • Rickettsiosis
  • Malaria 
  • Collagen vascular disease
  • Inflammatory bowel disease

Lymphocytosis occurs when lymphocytes are greater than 3.5 x 109/L. Common causes are as follows:

  • Accompanies monocytosis
  • Viral infections such as hepatitis A, cytomegalovirus (CMV), Epstein-Barr virus (EBV)
  • Bordetella pertussis

Neoplastic proliferations of white blood cells also cause leukocytosis. These are the malignant proliferations of abnormal clones of white blood cells within the bone marrow that are broadly categorized into lymphoid and myeloid neoplasms depending on the type of white cell proliferation. These malignancies are further characterized by the maturity and differentiation of the individual cell types and are divided into acute leukemias such as acute myeloid leukemia and acute lymphoblastic leukemia and chronic leukemias such as chronic myeloid leukemia and chronic lymphocytic leukemia.

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario. For further information about these lab tests contact Symbion VIP Diagnostics pathology lab Ahmedabad at 09429410291