Collection, Processing, and Storage Consideration for Urinary Biomarker Research

Summary

This protocol aims to provide considerations for urine sample collection, processing, and storage for urine tract infection biomarker studies.

Abstract

There are several urinary proteins that show promise as novel markers of urinary tract infections. The identification of a novel biomarker that has greater predictive accuracy compared to current diagnostic methods has the potential to greatly improve the ability to manage patients with urinary tract infections. However, sample collection, processing, and storage can all potentially impact the results of biomarker research. Understanding the effects of each of these stages on biomarker studies is necessary to inform future, high-quality research in this area, as well as to critically review other studies in this area. Here, the study reviews the literature regarding the effects of each stage of urine sample processing and reports the effects of various conditions on urinary proteins. The protocol will focus on collection techniques, time and temperature of storage, processing techniques, use of reagents, and long-term freezing on biomarker stability. It will focus on proteins but will briefly discuss other materials that may be utilized in biomarker research. In doing so, this protocol will provide a guide to future researchers to assist in the design of urinary biomarkers studies.

Introduction

Urinary tract infections (UTI) are one of the most common bacterial infections in both children and adults¹. While the diagnosis of UTI in some populations can be uncomplicated, it can be more complex in others, such as those with neuropathic bladders². The ability to accurately diagnose UTIs will help improve antibiotic stewardship efforts by decreasing the use of unnecessary antibiotics and potentially aid in the earlier diagnosis of UTI, thus decreasing the risk of morbidity. Given the prevalence of UTIs, there is significant interest in improving the management of this common infection.

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Protocol

This protocol follows the guidelines of the institution's human research ethics committee. Ensure that the approval is obtained from the institutional review board (IRB) prior to the collection and utilization of biological specimens for research.

1. Collection

1. Obtain urine sample in a sterile specimen cup. Decide the type of urine sample, as well as specific inclusion and exclusion criteria, based on the specific study design. For UTI studies, use either the clean-catch method.......

Discussion

The importance of producing consistent and reproducible results is not limited to the success of individual studies but will also enable a better comparison of results within the literature⁹. Variation between studies in key procedural steps can introduce irreversible bias that may affect biomarker signals and their interpretation, which may be responsible for discrepancies among several studies¹⁰. This demonstrates the need to establish a more standardized approach to proc.......

Materials

Name	Company	Catalog Number	Comments
Boric acid	Sigma-Aldrich	B6768	To be considered for samples that cannot be rapidly processed and frozen
Freezer boxes	Fisher Scientific	03-395-464
Microcentrifuge tubes	Thomas scientific	1149X93
NGAL ELISA Kit	R&D Systems	DLCN20	Used to create representative results
Pipette and tips	Dependent on pipette size and volume of fluid.
Sodium azide	Sigma-Aldrich	S2002	To be considered for samples that cannot be rapidly processed and frozen
Urine collection cups	Thermo Scientific	3122B03ORG	Sterile cups not required unless needed for other studies