Are tissue samples from two different anatomical areas of the kidney necessary for adequate diagnosis?

An accurate histological diagnosis is of fundamental importance for the therapy and prognosis of many kidney diseases. However, it remains unclear whether a single biopsy is representative of changes in the whole kidney.

To compare the quantity and quality of renal biopsy material taken from two separate areas from one kidney, we prospectively biopsied the renal cortex at the central third and at one of the kidney poles of 103 consecutive 61 native and 42 transplanted kidneys. With two biopsy cores from each kidney we sampled 14.5 ± 8.5 glomeruli/procedure.

The length of the biopsy core, the number of glomeruli/core and the markers of chronic renal damage (degree of interstitial fibrosis, proportion of global or segmental scared glomeruli) were not influenced by biopsy location (pole compared with central third locations). Moreover, there was no significant difference in the number of arteries in biopsies obtained from the two different biopsy areas. The percentage between renal cortex and medulla was not influenced by the biopsy area in all kidneys, but transplanted kidney biopsies contained more medulla than specimens from native kidneys. In patients with native kidneys and lower estimated creatinine clearances, there was a nonsignificant trend towards higher variations in the degree of interstitial fibrosis between the two cores, but a coincidence cannot be excluded. There was no significant difference in global sclerotic glomeruli in regard to the biopsy location.

We conclude that a renal biopsy composed of two cores from different areas of the kidney provides enough material for histological diagnosis. However, despite the variety of different renal diseases, sampling errors are minimal and obtaining two biopsies from different areas of the kidney does not lead to clinically useful information which would alter the management of patients.