Hematology: complete blood count (CBC) in Cats (Felis) | Vetlexicon
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Hematology: complete blood count (CBC)

ISSN 2398-2950

Contributor(s) :




  • Most information can be gained from PCV (need RBC count if send to laboratory, because PCV may be falsely elevated if cells swell in post, ie MCV); WBC and differential WBC count; WBC and RBC morphology; platelet estimate and morphology.
  • Anemia: PCV, reticulocyte count (aggregate count important in cats to determine whether regeneration is adequate or not), RBC count and morphology and Hb.


Source of test material

Quantity of test material

  • 2.5 ml (0.5-1.0 ml minimum) whole blood (EDTA or citrated).

Sample collection technique

  • Standard.
  • EDTA usually preferred for CBC, feline red cells shrink in the presence of excess concentrations of EDTA therefore correct volume is Hb.
  • Citrate for activated partial thromboplastin time, one-stage prothrombin time and tissue thromboplastin (other clotting tests require specialized collection or immediate testing).
  • Citrated sample may be useful for platelet counts if there is clumping with EDTA.

Quality control


  • Fill containers to correct level.
  • Replace cap immediately to prevent evaporation.
  • Mix correctly by gentle inversion several times.
  • Slow blood collection may lead to clotting; rapid collection may lead to hemolysis.

Timing of test

  • Best after 12 hour fast (to avoid lipemia).

Sample storage

  • Refrigerate if analysis delayed but note that refrigeration often promotes platelet clumping which may interfere with platelet count.
  • Make blood smear from freshly collected EDTA blood, submit with EDTA blood for CBC.

Sample transport

  • Ideally within 24 hours but standard mail adequate (12 hours or less for clotting times).



  • Widely available at commercial laboratories.
  • Blood smears can be examined in practice. Some in-hospital analyzers or cell counting methods now available.



  • Generally moderate to low unless blood parasites are recognized.


  • Generally moderate to low unless blood parasites are recognized.

Result Data

Abnormal values

  • Results may be diagnostic on their own or will rule out some differential diagnoses, or they will complement other laboratory tests.

Errors and artifacts

  • Poor sample handling:
    • Clotting makes sample unsuitable for evaluation.
    • Hemolysis will affect RBC indices.

Further Reading


Refereed papers

Other sources of information

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