White blood cells are produced in bone marrow, lymph nodes, the spleen and thymus. They fight infection and foreign bodies and help distribute antibodies throughout the body. Unused, a white blood cell lives for two to three weeks, and then disintegrates.

May be Increased in the Presence of:

• Infection
• Hemorrhage
• Trauma
• Some malignancies
• Exposure to toxic substances
• Thyroid storm
• Renal failure
• Some drugs (quinine, adrenalin and others)
• Chronic inflammatory disease
• Stress reactions
• Exercise
• Heat
• Cold
• Anesthesia
• Cigarette smoking

May be Decreased in the Presence of:

• Viral infections
• Bone Marrow Disease
• Bone Marrow Depression, secondary to:
  • Analgesics
  • Antibiotics
  • Antihistamines
  • Anticonvulsants
  • Antiinflammatory drugs
  • Antithyroid drugs
  • Arsenic
  • Barbiturates
  • Chemotherapy
  • Diuretics
  • Heavy metal contamination
  • Radiation exposure

Special Considerations

• Smokers typically have elevated hematocrits in response to chronic, low-grade carbon monoxide poisoning and other mild respiratory ailments. Because of the carbon monoxide binding, they may still be functionally anemic, even though their hematocrit levels look good.
• Adaptation to high altitudes includes moderate elevation of hematocrit.
• During the initial phases of an acute hemorrhage, the hematocrit generally doesn't change very much. Later, as extracellular fluid is mobilized and IV fluids are incorporated, there is a dilutional effect that will lead to a reduced hematocrit. This fall in hematocrit may take several hours to develop.

Normal Values*

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.