Abstract
Background:
The Central American bushmaster (Lachesis stenophrys) is one of the largest pitvipers in the Americas, with relatively low abundance, suspected population declines, and continuing loss, fragmentation, and habitat degradation.
Aim:
Conservation actions, both in the wild and in captivity, bear the need for health parameters that allow managers and veterinarians to have a better understanding of health, especially when there are relatively few individuals in captivity to obtain robust information since there is no published information on the genus. To have hematological and biochemical reference ranges on the genus Lachesis.
Methods:
Blood samples were collected from 32 individuals (18 females and 14 males under human care from seven zoological institutions from August 2022 to January 2023 and performed hematological and biochemical analyses.
Results:
Reference intervals of hematological analytes included packed cell volume (17.51-37.27%), total red blood cell count (0.36 - 0.92 1012/L), hemoglobin (61.73 – 145.23 g/L), white blood cell count (3.18 - 13.79109/L), lymphocytes (2.16 - 11.23%), azurophils (0.50 - 4.20%), monocytes (0.00 - 0.21%), heterophils (0.05 - 1.12%), eosinophils (0.00 - 0.19%), basophils (0.00 - 2.00% ) and total thrombocyte count (0.68 - 6.68 109/L) and biochemistry reference intervals included total protein (41.76 - 111.31 g/L), albumin (11.46 - 28.69g/L) , globulins (29.25 - 85.14g/L), AST (1.44 - 68.75U/L), CK (52.72 - 625.00U/L), uric acid (20.02 - 438.53 µmol/L), glucose (0.68 - 3.29 mml/L), cholesterol (41.74 - 13.25mmol/L), calcium (1.78 - 6.06mmol/L), and phosphorus (0.72 - 2.26mmol/L).
Conclusion:
This is the first report on the genus Lachesis reporting hematological and biochemical reference ranges.

Key words: Biochemistry, Bushmaster, Costa Rica, Hematology, Lachesis stenophrys