Hematologic Parameters and Blood Cultures from the Gingival Vein Compared with the Cranial Vena Cava in Guinea Pigs

Blood collection methods in guinea pigs are limited due to the animals' compact neck, short limbs, and lack of a tail. Gingival venipuncture is a recently described blood sampling technique that is minimally traumatic with no significant alterations in hematologic parameters when multiple blood samples were collected weekly for 6 wk. The purpose of this study was to determine whether the gingival vein can be used as an alternative blood collection site in guinea pigs, such that: (1) hematologic parameters would be consistent with samples collected from the cranial vena cava; and (2) no contaminants from the oral cavity would be introduced into the sample. Blood samples were obtained from both the gingival vein and cranial vena cava of anesthetized Dunkin Hartley guinea pigs for CBC (n = 9) and aerobic blood cultures (n = 10). Only MCV was significantly different between sampling sites. Bland-Altman analyses calculated a small mean bias for all hematologic parameters, indicating clinical interpretation is unlikely to be affected by the sampling site. Bacterial growth occurred in all 5 gingival vein blood samples prepared by using saline and 2 of the 5 prepared with dilute chlorhexidine. Bacteria did not grow from any cranial vena caval blood samples prepared with dilute chlorhexidine. No clinical signs of hemorrhage or trauma were detected at either site. These results provide evidence that gingival venipuncture can be used as an alternative blood collection method for guinea pigs for hematologic analysis but should not be used for blood culture.