[Application and preparation of a BUN Test Strip]

Blood urea nitrogen (BUN) levels are commonly assessed in clinical settings to evaluate kidney function and hydration status. Traditional methods require laboratory equipment and trained personnel, limiting rapid assessment in field or home settings. Prior research has shown that enzymatic dry chemistry can offer a portable alternative. However, no prior work had resolved the issue of interference from endogenous blood components in such assays. Existing methods often lack precision for immediate use. This gap motivated the development of a stable, portable BUN test strip. Researchers have already demonstrated that urease-based reactions can detect BUN. Yet, no prior work had resolved the issue of stabilizing reagents on paper substrates. That uncertainty drove the need for a new approach to immobilize reagents and protect against interference. This paper introduces a novel dry chemical method for BUN determination.

The aim of this study is to develop a reliable and portable method for measuring blood urea nitrogen (BUN) using a dry chemical test strip. The specific problem addressed is the lack of a stable, rapid, and interference-resistant method for BUN testing outside of clinical laboratories. The motivation stems from the need for point-of-care diagnostics that can provide immediate results without requiring complex instrumentation. The researchers sought to create a test strip that could be used in diverse settings, including field clinics and home health monitoring. A key challenge was ensuring the strip remained stable after preparation and could resist interference from blood components. The study also aimed to validate the strip’s precision and correlation with established methods like the Ames BUN Strip. By addressing these issues, the researchers hoped to offer a practical alternative to traditional BUN testing. The ultimate goal is to improve accessibility and speed of BUN measurement in clinical and non-clinical environments.

The researchers immobilized urease, indicator, buffer, and stabilizers on a specialized paper substrate. A thin protective film was applied to prevent interference from endogenous blood materials. The paper was dried and cut into small strips for use. The enzymatic reaction occurs when a blood sample is applied to the strip. Color changes were observed within one minute using a color plate for semiquantitative analysis. Precision was evaluated using coefficients of variation (CV%) for one-day and day-to-day testing. Correlation with the Ames BUN Strip was assessed using linear regression. The study utilized a standardized protocol for reagent immobilization and film application. No prior work had resolved the issue of stabilizing these reagents on a paper-based platform. The method was designed to ensure rapid and reliable BUN detection without complex equipment. The protective film was a novel addition to prevent interference from blood components.

The BUN test strip provided results within one minute using a color plate for semiquantitative analysis. One-day precision had a coefficient of variation (CV%) of 2.6% to 5.0%. Day-to-day precision ranged from 5.9% to 7.1%. The correlation with the Ames BUN Strip was strong, with a correlation coefficient of r = 0.98. The linear regression equation was y = 0.96x - 2.4, where x represents the Ames BUN Strip values. The protective film effectively reduced interference from endogenous blood materials. The enzymatic reaction remained stable after the reagents were immobilized on the paper. The method demonstrated sufficient precision for clinical use. These findings suggest the test strip could be a viable alternative to traditional BUN testing methods.

The study concludes that the BUN test strip is a practical and reliable method for measuring blood urea nitrogen. The protective film successfully minimizes interference from blood components. The strip provides results within one minute, suitable for point-of-care testing. The precision values indicate acceptable reliability for clinical use. The strong correlation with the Ames BUN Strip supports its validity. The method’s simplicity and portability make it suitable for diverse settings. The authors propose that this test strip could replace traditional methods in certain diagnostic scenarios. The findings suggest the strip is a viable alternative for BUN measurement.