Platelet Estimate:
After you have finished the differential count, continue your blood smear analysis
with an estimate of the platelet count as low, normal, or high.
To estimate platelet number, determine the average number of platelets in 5 to 10 oil
immersion fields. At this magnification, each platelet is approximately equal to
15,000 platelets/µl. The following guidelines are useful for this session:
| Species | "Adequate"
platelets / field
|
|---|
| Canine, feline, bovine | ~10-30 |
| Equine | ~6-20 |
The platelet estimate should be done in the part of the smear used for differential
counting and evaluation of morphology. This method of estimating platelets
is less precise if platelet clumps are present, though an estimate based on the dispersed
platelets in such a smear does provide a 'not less than' estimate. On Cornell CBC's,
the following reporting protocol is used:
- Incr.: count clearly above reference range for the species.
- Adeq.: count clearly within reference range
- Low? : count near low end of reference range. If in fact below range, only mildly so.
- Low : count clearly below reference range.
- Very Low: count in range where risk of spontaneous hemorrhage is significant (ie, <25,000/microliter).
|
Upper panel: normal platelet count.
Lower panel: severe thrombocytopenia.
|