Comparison of aspiration and nonaspiration techniques for obtaining cytologic samples from the canine and feline spleen

BACKGROUND: Ultrasound-guided fine needle aspiration of the spleen is commonly used in the diagnostic evaluation of veterinary patients. Techniques using suction delivered through a 6-20-cm(3) syringe are the most commonly described means of obtaining cytologic samples of the spleen. Comparison studies of various human lesions have shown nonaspiration techniques to produce equal or superior cytologic specimens with less blood than specimens obtained using aspiration techniques. OBJECTIVE: The purpose of this study was to compare the quality of splenic cytology specimens obtained using aspiration and nonaspiration techniques. METHODS: Client-owned dogs (n=24) and cats (n=7) receiving an abdominal ultrasound at the University of Tennessee College of Veterinary Medicine were enrolled in the study between January and June 2005. Samples were obtained from patients with and without sonographic splenic abnormalities. Two clinical pathologists, working independently and blinded to the method of sample collection, graded the cytologic specimens using a subjective scoring system for cellularity, amount of blood, and preservation of cellular morphology. RESULTS: Agreement between the 2 independent observers was good. Direct comparison of the 2 techniques showed that samples obtained by the nonaspiration method had higher cellularity (P=.0002), less blood (P=.0023), and similar cell morphology (P=1.0000) compared with samples obtained by the aspiration method. CONCLUSION: These results suggest the nonaspiration technique is a superior method for obtaining a high-quality cytologic specimen from the canine and feline spleen