For detailed information on each type of WBC go to the specific section on each type of WBC:
The WBC count and differential are a routine part of the complete blood count (CBC) test.
1. Basophils:
Granulocytes whose function is not fully understood. They are capable of ingesting foreign particles and secreting histamine. Basophils are associated with mast cells, express IgE and play a role in allergic inflammatory disease.
2. Eosinophils:
Granulocytes that dispose of cellular debris; but also seems to be involved in allergic responses. These cells have a potent cytotoxic effect, especially on parasites, by the release of destructive proteins (major basic protein, eosinophil cationic protein and eosinophil derived neurotoxin) into the extracellular space.
3. Lymphocytes:
Agranulocyte that is separated into B-lymphocytes (make antibodies to attack bacteria/toxins) and T-lymphocytes (responsible for cell-mediated immunity such as attacking cells infected by viruses or attacking cancerous cells).
4. Monocytes:
Agranulocyte that seeks antigens in the blood stream and eventually migrates to the tissues and becomes a macrophage. Monocytes serve as an antigen-presenting cell for T lymphocytes.
5. Neutrophils:
Granulocyte that is typically the most common leukocyte in circulation. These cells are involved in inflammatory processes and in the phagocytosis and destruction of bacteria. Total neutrophil count is made up of the total number of segmented neutrophils plus band forms.
The White blood cell (WBC) count and differential may be clinically useful in:
Additional information:
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
Total WBC Count
| Conv. Units (cells/mm3) | Conv. Units (cells/103/mm3) | SI Units (Cells x 109/L) | |
|---|---|---|---|
| Birth | 9,000-30,000 | 9.0-30.0 | 9.0-30.0 |
| 2-8 weeks | 5,000-21,000 | 5.0-21.0 | 5.0-21.0 |
| 2-6 months | 5,000-19,500 | 5.0-19.5 | 5.0-19.5 |
| 7-12 months | 6,000-17,500 | 6.0-17.5 | 6.0-17.5 |
| 1-5 years | 5,500-15,500 | 5.5-15.5 | 5.5-15.5 |
| 6-17 years | 4,500-14,000 | 4.5-14.0 | 4.5-14.0 |
| Adult | 4,500-11,000 | 4.5-11.0 | 4.5-11.0 |
WBC Differential (%) [Conventional Units]
| Segmented Neutrophils (Polys/Segs) | Bands (Stabs) | Lymphocytes | Eosinophils | Basophils | Monocytes | |
|---|---|---|---|---|---|---|
| Birth | 32-62% | 10-18% | 26-36% | 0-2% | 0-1% | 0-6% |
| 2-8 weeks | 15-35% | 7-16% | 38-71% | 0-3% | 0-1% | 0-9% |
| 2-6 months | 15-35% | 5-11% | 42-72% | 0-3% | 0-1% | 0-6% |
| 7-12 months | 13-33% | 6-12% | 46-76% | 0-3% | 0-1% | 0-5% |
| 1-5 years | 13-33% | 5-11% | 46-76% | 0-3% | 0-1% | 0-5% |
| 6-17 years | 32-54% | 5-11% | 27-57% | 0-3% | 0-1% | 0-5% |
| Adult | 50-65% | 3-5% | 25-40% | 0-4% | 0-1% | 2-8% |
WBC Differential (fraction) [SI Units]
| Segmented Neutrophils (Polys/Segs) | Bands (Stabs) | Lymphocytes | Eosinophils | Basophils | Monocytes | |
|---|---|---|---|---|---|---|
| Birth | 0.32-0.62 | 0.10-0.18 | 0.26-0.36 | 0-0.02 | 0-0.01 | 0-0.06 |
| 2-8 weeks | 0.15-0.35 | 0.07-0.16 | 0.38-0.71 | 0-0.03 | 0-0.01 | 0-0.09 |
| 2-6 months | 0.15-0.35 | 0.05-0.11 | 0.42-0.72 | 0-0.03 | 0-0.01 | 0-0.06 |
| 7-12 months | 0.13-0.33 | 0.06-0.12 | 0.46-0.76 | 0-0.03 | 0-0.01 | 0-0.05 |
| 1-5 years | 0.13-0.33 | 0.05-0.11 | 0.46-0.76 | 0-0.03 | 0-0.01 | 0-0.05 |
| 6-17 years | 0.32-0.54 | 0.05-0.11 | 0.27-0.57 | 0-0.03 | 0-0.01 | 0-0.05 |
| Adult | 0.50-0.65 | 0.03-0.05 | 0.25-0.40 | 0-0.04 | 0-0.01 | 0.02-0.08 |
A critical result relates to the clinical scenario; however, WBC's above 100,000 per mm3 (100 X 109 /L) are a medical emergency due to risk of brain infarction (due to sludging) and hemorrhage.
Increased total WBC's is called leukocytosis.
The line of cells (e.g. neutrophils, lymphocytes, etc) that is elevated is important (see the specific sections on those subtypes of WBC for further information).
WBC's>100,000/mm3 is a medical emergency and immediate hematology/oncology consultation is needed.
Conditions that cause leukocytosis include:
Decreased total WBC's is called leukopenia.
The line of cells (e.g. neutrophils, lymphocytes, etc) that is decreased is important (see the specific sections on those subtypes of WBC for further information).
Conditions that cause leukopenia include: