What is the primary function of a reagent strip in urine analysis?

The primary function of a reagent strip in urine analysis is to change color based on the pKa changes of dissolved substances, which reflects the presence and concentration of various analytes in the urine. Reagent strips are coated with specific chemical reagents that interact with substances in the urine, such as glucose, protein, pH, and ketones.

When these substances are present, they cause a chemical reaction that results in a color change on the strip. This color change can be visually interpreted or quantitatively analyzed against a color chart to determine the concentration of the substance in the urine. This makes the reagent strip a vital tool in clinical settings, providing quick and efficient testing for multiple parameters simultaneously.

Other options do not align with the primary function of a reagent strip. For example, measuring the temperature of the urine sample is not a function of the strip itself, nor is it involved in determining specific gravity, which requires a different method or instrument. Similarly, while filtering urine is a necessary step at times in laboratory settings, it is not a function associated with reagent strips, which are designed for immediate analysis and result interpretation.