FETAL RENAL BIOPSY - TECHNIQUE DEVELOPMENT

Fetal/neonate kidneys obtained at the time of autopsy were utilized to determine a suitable needle biopsy gauge to obtain renal parenchyma f or histologic evaluation. Twenty-one fresh kidney specimens from 11 fe tuses/neonates between 16-40 weeks gestation were used to obtain needl e biopsies using 20-, 18-, 16-, and 14-gauge biopsy catheters. The spe cimens were graded according to the presence of normal histologic feat ures of renal parenchyma. Seventy-five renal biopsies were obtained. T he biopsy histology was interpreted using a grading system based on th e presence of normal features of the renal parenchyma. Sixty-three (84 %) of the samples were graded histologically as adequate (cortex or me dulla present). Samples with both cortex and medullary structures pres ent (completely adequate) were obtained in 39/63 (62%) of these adequa te biopsies. The 14- and 16-gauge biopsy catheters gave the best resul ts, respectively yielding 79 and 69% completely adequate biopsies. Thi s is in contrast to the 20- and 18-gauge catheters that respectively y ielded 35 and 25% completely adequate biopsies. Our initial results in dicate that adequate kidney biopsies can be obtained. However, the cur rent technique is associated with core sample disruption when the smal ler gauge catheters are used. This could account for the low rate of c ompletely adequate samples with the smaller gauge catheters. A differe nt sampling technique is needed to overcome sample disruption, to dete rmine the smallest catheter gauge that will yield a suitable tissue sa mple for histologic evaluation.