• Leukocytes, Neutophils
• Neutrophils
• Bands
• Polys
• Segmented neutrophils
• Segs

• Lavender top tube
• 5 mL of whole blood

The WBC count and differential are a routine part of the complete blood count (CBC) test.

• Neutrophils are granulocytes and in adults, make up the majority of circulating leukocytes.
• Neutrophils are involved in inflammatory processes, phagocytosis, and destruction of bacteria.
• The Total Neutrophil Count (TNC) is the # of Segmented Neutrophils + # of Band Forms.
• Immature neutrophils, which consist of bands, metamyeloctes, melocytes and rarely promyelocytes, may be released into circulation during acute stressors such as major infection, trauma, burns, hypoxia, vomiting, etc.

General Notes on WBC's

• WBC's (also known as leukocytes) are produced in bone marrow and are part of the primary defense mechanism against foreign organisms, tissues, and other substances.
• WBC's produce, transport, and distribute antibodies as part of the immune response to a foreign substance or antigen.
• WBC's are categorized into Granulocytes (which can secrete biologically active substances such as histamines or cyclooxigenase) and agranulocytes (which do not have granules that can be secreted).
• Leukocytes or WBCs are differentiated into 5 different types:
1. Basophils
2. Eosinophils
3. Lymphocytes
4. Monocytes
5. Neutrophils

Neutrophils are the WBC's involved in defense against bacterial infection. Elevations in neutrophil count (Neutrophilia) are non-specific as virtually any major body stressor can lead to neutrophilia.

The White Blood Cell (WBC) count and differential, which the neutrophil count is part of, has clinical utility in:

• Evaluation of infection or inflammation
• Assist in determination of viral versus bacterial infection
• Assist in evaluation of the stage and severity of an infection
• Detect allergic response or parasitic infections (elevated eosinophils)
• Evaluation for hematologic malignancy/disorders
• Detecting and identifying various types of myelopoietic disorders
• Detecting and identifying various types of leukemia
• Evaluating bone marrow depression
• Evaluation of need for further tests, such as manual WBC differential or bone marrow biopsy
• Evaluation of drug effects, response to chemotherapy or radiation
• Evaluation of effect of cytotoxic agents
• Screening test as part of a CBC on admission to a health care facility or before surgery

Additional information:

• The interpretation of a normal, high or low result of any given WBC type requires the context of the patient's clinical condition, history and physical examination
• Specific patterns of leukocyte response are seen in various types of diseases as determined by the differential count
• The life span of leukocytes is normally 13–20 days, after which the cells are destroyed in the lymphatic system and are excreted from the body in fecal matter.

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

WBC Differential

• Increased neutrophil count is referred to as neutrophilia.
• Neutrophilia may be due to infection, inflammation, drugs, toxins, physical agents, burns, trauma, vomiting, emotional stimuli, endocrine, metabolic, neoplastic, or hematologic disease.
• Pseudoneutrophilia, occurs due to a release of the storage pool of neutrophils into circulation due to an acute stress (especially trauma, vomiting, epinephrine, exercise, anesthesia, etc).

Conditions, which cause neutrophilia, include:

• Pathological:
• Acute infections
• Bacterial
• Mycotic
• Parasitic
• Rickettsial
• Spirochetal
• Viral
• Acute inflammatory disorders
• Acute rheumatoid arthritis
• Hypersensitivity reactions
• Myositis
• Rheumatic fever
• Vasculitis
• Allergies
• Drugs and toxins
• Drugs and toxins that lead to neutrophilia include
• Amphetamines
• Beta agonists (e.g. Albuterol)
• Cocaine
• Corticosteroids
• Digitalis
• Epinephrine
• Heparin
• Histamines
• Lithium
• Hematologic disorders
• Hemolytic anemia
• Leukemias
• Myeloproliferative disorder
• Post-hemorrhage
• Metabolic disturbances
• Adrenal crisis
• Diabetic ketoacidosis
• Eclampsia
• Thyroid storm
• Uremia
• Neurologic
• Head trauma
• Intracranial hemorrhage
• Seizure
• Smoking
• Tissue necrosis
• Burns
• Gangrene
• Malignant neoplasia
• Myocardial infarction
• Physiological:
• Anger
• Crying babies
• Electric shock
• Excitement
• Exercise
• Exposure to extreme heat or cold
• Fear
• Joy
• Menstruation
• Newborn
• Obstetric labor and delivery
• Stress
• Ultraviolet light
• Vomiting

Conditions associated with increased number of bands, include:

• Acidosis (e.g. DKA)
• Acute inflammatory states
• Anoxia
• Hemorrhage
• Necrosis
• Parenteral nutrition
• Postoperative period (12-36 hours)
• Seizure
• Sepsis or serious infection
• Stimulants (Amphetamines, Beta agonists, Cocaine)
• Trauma

• A decreased neutrophil count is referred to as neutropenia.
• Neutropenia is a neutrophil count of <1,000 neutrophils/mm³ (<1.0x10⁹/L).
• A neutrophil count of <500 neutrophils/mm³ (<0.5x10⁹/L) often indicates agranulocytosis.
• Neutropenia often allows serious bacterial infections to occur with the outcome being death due to sepsis.

Conditions associated with neutropenia include:

• Chemical and physical agents
• Bone marrow depressants
• Benzene
• Cytotoxic drugs
• Radiation
• Drugs
• Chloramphenicol
• Clozapine
• Erythropoietin
• Phenothiazines
• Infections
• Bacterial
• Brucellosis
• Paratyphoid
• Septicemia - mainly gram negative
• Typhoid fever
• Viral
• Chickenpox
• Colorado tick fever
• Hepatitis
• HIV
• Infectious mononucleosis
• Influenza
• Measles
• Rubella
• Others
• Protozoa – malaria
• Rickettsia
• Myeloid hypoplasia
• Agranulocytosis
• Aplastic anemia
• Space-occupying bone marrow lesions
• Vitamin B₁₂ and folic acid deficiency
• Other conditions
• Alcoholism
• Autoimmune neutropenia
• Benign familial leukopenia
• Chronic idiopathic neutropenia
• Collagen-vascular diseases as lupus erythematosus
• Cyclic neutropenia
• Hypersplenism
• Liver disease
• Storage diseases
• Hypothermia
• Myelodysplasia
• Rheumatoid arthritis
• Severe congenital neutropenia - Kostmann's syndrome
• Starvation

Although rare, the conditions of cyclic neutropenia and chronic idiopathic neutropenia are defined below:

1. Cyclic Neutropenia:

This condition is an autosomal dominant condition in which every 21-30 days, the carrier has 3-6 days of neutropenia. During these times they are susceptible to infections.

2. Chronic idiopathic neutropenia:

A condition with neutrophils <1,000 neutrophils/mm³ (<1.0x10⁹/L) chronically; however, few infections occur.

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