Comparison of the diagnostic yield of 3 and 5 mm laparoscopic liver biopsy forceps in cats

Objective: To determine whether 3 and 5 mm laparoscopic cup biopsy forceps provide samples of equivalent diagnostic quality in cats.Study design: Experimental study.Animals: Twelve colony cats undergoing a concurrent nutrition study.Methods: Two biopsy forceps (3 and 5 mm) and three biopsy techniques (twist, pull, and twist + pull) were used to collect 68 laparoscopic liver samples. Biopsies were performed consecutively with the 3 and 5 mm biopsy sites adjacent to each other. Data analyzed included the number of portal triads and hepatic lobules, tissue crush and fragmentation, overall sample area (mm(2) ), sample weight, and agreement regarding morphologic diagnosis.Results: The 5 mm forceps provided more hepatic lobules, portal triads, and a larger tissue weight and histologic area (mm(2) ) (p < .01). The twist and pull techniques provide more hepatic lobules and portal triads compared to the twist + pull technique while the twist + pull technique resulted in greater tissue crush compared to the twist technique (p = .0097). There was good agreement for morphological diagnosis between the 3 and 5 mm samples using the twist + pull technique but not for the twist or pull techniques.Conclusion: Liver samples can be safely collected with 3 or 5 mm laparoscopic biopsy forceps and provide sufficient tissue for histopathology analysis in cats, with minimal artifact. The diagnostic accuracy of 3 mm samples remains unknown.