*Purpose: The purpose of this study is to characterize human kidney anatomic variability both within singular biopsies and between biopsy sites in order to investigate how the information obtained from a biopsy can best be used to draw experimental conclusions in human organ research.

*Methods: Biopsy collection is a simple and effective method for obtaining information in human organ experimentation. Single biopsies are used as a metric to assess organ viability and determine effectiveness of diagnostic tools or therapies. Current practices assume that data obtained from a singular biopsy is representative of a kidney as a whole. The variability within a singular biopsy and within a kidney was determined using the following methods. Cortical wedge biopsies were taken from transplant-declined human kidney in 5 locations (Figure 1A). The biopsies were fixed in 10% formalin. 4 µm sections were sliced every 200 µm for the length of each biopsy and stained with H&E. The whole sections were imaged using a 20x tiling program. The number of healthy glomeruli were counted, and the total area of each biopsy section was determined. Healthy glomerular density per section was calculated. The H&E 20x images were inputted into our digital pathology tool developed in MATLAB to gather preliminary nuclear density quantification data (Figure 1B and 1C). Biopsy sections were also stained with picrosirius red and imaged at 20x in order to quantify areas of fibrosis.

*Results: The density of healthy glomeruli per section was plotted vs. the biopsy location (Figure 1D). The data demonstrate that the density of healthy glomeruli is variable both within a single biopsy and between biopsy locations. The preliminary nuclear density and area of fibrosis data obtained from our digital pathology tool demonstrate similar variability.

*Conclusions: The results suggest that biopsy location selection and biopsy sectioning processes appear to contribute to variable characterization of a kidney. Additional kidney will be studied to identify trends and refine methods. Omics analysis will be used to supplement quantitative histological data and enhance our understanding of variability at a molecular level.

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