ISSN 2398-2985      



Synonym(s): Complete blood count (CBC), Hemogram


  • Study of blood cells.
  • Red cells via:
    • Packed cell volume (PCV).
    • Red blood cell (RBC) count.
    • Hemoglobin (Hb) concentration.
    • RBC indices: MCV (mean cell volume or mean corpuscular volume), MCH (mean cell hemoglobin or mean corpuscular hemoglobin) and MCHC (mean cell hemoglobin concentration or mean corpuscular hemoglobin concentration).
    • Reticulocyte count (either on routine request or when evidence of anemia is present).
  • White cells via:
    • Leukocyte (white blood cell, WBC) count (WBCC).
    • Differential WBC count: relative amounts of various WBC present.
  • Platelet count and morphology Hematology: platelet count.
  • Tests of clotting function (values in seconds):
    • Whole blood clotting time (WBCT).
    • Prothrombin time (PT).
    • Activated partial thromboplastin time (APTT).
Reference intervals for the total red blood cell count T(RBC), Hemoglobin (Hb), and packed cell volume (PCV) are difficult to establish for reptiles and other ectotherms because profound physiologic adaptations may occur in response to a number of intrinsic and extrinsic factors.


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  • Manual: most frequently evaluation of blood smears. Use direct (eg Natt-Herrick) Staining technique: standard Natt and Herrick's stain or indirect (eg Phloxine B) methods.
  • Mechanical: automated cell counters cannont be used for differential cell counts due to nucleated RBCs.


  • Widely available at commercial laboratories; check availability of reptile expertise before sending samples.
  • Blood smears can be examined in practice.

Technique (intrinsic) limitations

  • Intrinsic factors include species, gender, age, and the physiologic status of the reptile. Extrinsic factors include season, temperature, habitat, diet, disease, stress associated with captivity, and the venipuncture site.
  • When establishing reference intervals, the intrinsic and extrinsic factors affecting the reference population must be documented in order to ensure that the physiologic data are collected under consistent circumstances. It has been recommended that a minimum of 97 samples is required from a reference population to provide statistically meaningful intervals.
Allowances for 20 or 40 samples to be used in the establishment of reference intervals have been recommended by the American Society of Veterinary Clinical Pathology (ASVCP); however, the preferred standard is use of 120 samples or more.

Result Data

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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Stacy N I, Alleman A R & Sayler K A (2011) Diagnostic hematology of reptiles. Clin Lab Med 31 (1), 87-108 PubMed.

Other sources of information

  • Campbell T (2015) Peripheral Blood of Reptiles. In: Exotic Animal Hematology and Cytology. 4th edn. Wiley-Blackwell, USA. pp 85.
  • Campbell T W (2012) Hematology of Reptiles. In: Veterinary Hematology and Clinical Chemistry. 2nd edn. Eds: Thrall M A, Weiser G, Allison R & Campbell T. Wiley-Blackwell, USA. pp 277-297.

Reproduced with permission from Terry W Campbell: Exotic Animal Hematology and Cytology © 2015, published by John Wiley & Sons.

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