Comparison of diagnostic quality of kidney biopsy obtained using 16G and 18G needles in patients with diffuse renal disease.

To determine the diagnostic quality and complication rates of 16G and 18G needles in biopsy of the kidney, we performed renal biopsy using a biopsy gun under ultrasound guidance in 50 patients who were prospectively and evenly assigned to one of the two needle biopsy methods from April 2007 until May 2008. Two cores of renal biopsy specimen were obtained in each case and subjected to histopathological and immunoflourescence (IF) examination. Pain associated with the procedure was assessed using a visual analog scale. The number of glomeruli retrieved using the 16G needle ranged from 0 to 30 (mean 9.42 ± 5.5) and those retrieved using 18G needle ranged from 0 to 19 (mean 7.72 ± 4.4), P <0.05. The quality of biopsy was poorer with 18G needle as compared with 16G needles because of a higher amount of fragmentation and crushing artifact. There was no difference in the complication rates between the two needles (2% each). The 16G needle was associated with significantly more pain than the 18G needle. We conclude that our study demonstrates the benefit of the larger 16G needle in providing more tissue and glomeruli, which is more diagnostically useful. However, the use of 16G needle was associated with significantly more pain than the 18G needle, and may be a better compromise for diagnostic usefulness and patient acceptability.