• Thrombocytes of reptiles are small (generally smaller than erythrocytes), elliptical to fusiform cells with a centrally located oval nucleus containing dense nuclear chromatin that stains purple.
• Some nuclei may contain a pale line that extends across the width of the nucleus.
• The cytoplasm is typically colorless to pale blue in color and may contain a few azurophilic granules.
• Activated thrombocytes are common and appear as aggregated clusters of cells with decreased cytoplasmic volume, irregular cytoplasmic margins, and vacuoles.
• Indistinct cytoplasmic margins may be noted on some individual thrombocytes and are probably a product of age, artifact, or function.
• Reptilian thrombocytes function similarly to avian thrombocytes and mammalian platelets and play a significant role in thrombus formation.
• Activated reptilian thrombocytes exhibit ultrastructural features such as pseudopodia with fine granular material and many fibrin-like filaments that radiate between and around the cells.

Uses

Alone

• Assessment of platelet numbers can give an indication of disease and coagulation problems.

In combination

• With prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrin degradation product (FDP) in diffuse intravascular coagulation (DIC).

Other points

• Kidney involved in manufacture of thrombopoietin/thrombocytosis stimulating factor (TSF).
• Platelets live longer than WBCs, therefore in bone marrow suppression leukopenia is usually present before thrombocytopenia.
• Rarely, thrombocytosis can be seen in the following non-pathological conditions: excitement/exercise (splenic contraction), following splenectomy Splenectomy (loss of storage pool) and during late pregnancy.