Canis ISSN: 2398-2942

Hematology: platelet count

Synonym(s): Thrombocyte

Contributor(s): Kathleen P Freeman

Overview

  • Assessment of platelet numbers.

Sampling

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Tests

Methodologies

QBC-V system

  • Quick but very unreliable.

Manual count

  • With commercial blood dilution system + standard Neubauerer chamber gives accurate platelet count.
  • Most automatic counts should be checked manually on a smear.
  • On Romanowsky or supravitally stained smear:
    • Count platelets and WBCs over same oil immersion field (100x) (10-30 platelets per field in normal dog).
    • Average number of platelets per oil field x 20,000 = estimate of platelet count x10*9/l.
    • 6-7 platelets per field = ~ 100 x 10*9/l.
    • Check edges of smear for platelet clumping → may produce artificially low platelet counts.
      Estimates only, considerable errors, but clinically useful.

Automated blood counter

  • Rapid but if platelet clumping occurs → low readings.

Availability

  • Widely available at commercial laboratories.
  • Manual counting can be performed in practice.

Validity

Sensitivity

  • Low to high, depending on age of specimen, platelet clumping and correlation with other techniques.

Specificity

  • Low.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Couto C G (1999) Managing thrombocytopenia in dogs and cats. Vet Med 5, 460-465.

Other sources of information

  • Cowell R J, Tyler R D & Meinkoth J H (1999) Diagnostic Cytology and Hematology of the Dog and Cat. 2nd edn. St Louis: Mosby.
  • Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine Clinical Pathology. 3rd edn. Ames, Iowa: Iowa University Press.
  • Jain N C (1993) Essentials of Veterinary Hematology. Philadelphia: Lea & Febiger.


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