Minicore needle biopsy of kidney transplants: a safer sampling method.

We evaluated a fine No. 18 biopsy needle and spring loaded biopsy gun for percutaneous sampling of kidney transplants. The minicore sample produced is less than 0.5 mm. in diameter and up to 17 mm. long. The minicores are readily processed for histological study and sample size is adequate for multiple sectioning. We performed 50 separate minicore biopsy procedures in 37 patients with a single complication, a transient clot obstruction of the ureter. Of the biopsies 46 (92%) were adequate for diagnosis; 43 (86%) had more than 4 glomeruli per minicore. All renal structures were clearly defined and representative. A spectrum of pathological conditions affecting transplanted kidneys was identified in the different minicores. The minicore biopsy provided a safe, reliable method for diagnosis and monitoring of post-transplant intrarenal events.