Abstract 5885: Streck Urine Preserve provides cell-free DNA stabilization in whole urine for liquid biopsy

Abstract Urinary cell-free DNA (ucfDNA) has gained recognition as a critical biomarker for liquid biopsy, as it provides comprehensive and invaluable insights for cancer researchers, especially for urological cancers such as bladder, kidney, and prostate cancers. While urine as a sample matrix offers appealing advantages over blood, including large sample volume and truly non-invasive and easy self-collection, ucfDNA is a challenging and unstable analyte, as it is vulnerable to DNase degradation and contamination from bacterial and genomic DNA. Here, we describe the use of Streck Urine Preserve to minimize pre-analytical variables before ucfDNA extraction and downstream analysis. To determine whether Streck Urine Preserve effectively stabilizes ucfDNA and limits DNA contamination, second void urine was collected from donors, treated with Streck Urine Preserve, and stored at 2 °C to 37 °C for up to 7 days. Following storage, ucfDNA was isolated from 4 or 8 mL urine using a modified automated extraction method with MAGicBead cfDNA Isolation Kit (Zymo Research) on a KingFisher Apex System. Target human ucfDNA concentrations were monitored by ddPCR or dPCR using a housekeeping gene (ACTB) as a surrogate marker. The total bacterial burden in the extracted ucfDNA sample was analyzed using qPCR targeting 16S rRNA. While unpreserved urine samples exhibit rapid ucfDNA degradation during ambient temperature storage, samples stored in Streck Urine Preserve (at a preservative-to-urine ratio range between 1:20 to 1:5) maintained the void-time human ucfDNA target concentration for up to 7 days regardless of temperature (2 °C to 37 °C). Further, a marked increase in bacterial cfDNA contamination was observed in the unpreserved urine sample, whereas samples treated with Streck Urine Preserve displayed minimal changes in Cq values of 16S rRNA in the extracted ucfDNA from void time to day 7. Taken together, these data indicate that Streck Urine Preserve protects ucfDNA targets in the sample from DNase degradation and genomic and bacterial DNA contamination during storage. Streck Urine Preserve ensures sample integrity and minimizes pre-analytical variables, providing cancer researchers and assay developers flexibility in sample handling and enhanced confidence in the validity of downstream ucfDNA analysis results. Streck Urine Preserve is for Research Use Only. Not for use in diagnostic procedures. Streck Urine Preserve should only be used for research or the development of new assays. Citation Format: Jing Li, Sama Mehta. Streck Urine Preserve provides cell-free DNA stabilization in whole urine for liquid biopsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5885.