The WBC count and differential are a routine part of the complete blood count (CBC) test.
Eosinophils are 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.
The eosinophil count is primarily useful in assessing allergic response or parasitic infection. Increased eosinophils, otherwise known as eosinophilia, is more likely to be due to parasitic infection in the pediatric patient and more likely to be due to drug reaction in adults or children on medications.
The White Blood Cell (WBC) count and differential, which the eosinophil count is part of, has clinical utility in:
Additional information:
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
WBC Differential
| Conv. Units (%) | SI Units (fraction) | |
|---|---|---|
| Birth | 0-2 | 0-0.02 |
| 2-8 weeks | 0-3 | 0-0.03 |
| 2-6 months | 0-3 | 0-0.03 |
| 7-12 months | 0-3 | 0-0.03 |
| 1-5 years | 0-3 | 0-0.03 |
| 6-17 years | 0-3 | 0-0.03 |
| Adults | 0-4 | 0-0.04 |
Conditions, which may cause increased number of eosinophils (eosinophilia), include: