A patient serum CK measurement is out of range and a dilution is required. Which water would be appropriate to prepare the dilution?

A patient serum CK measurement is out of range and a dilution is required. Which water would be appropriate to prepare the dilution?

• A. Deionized water
• B. Tap water
• C. Type I water
• D. Type III water

Answer: (C)

In a dilution for an enzymatic assay like CK, the water used must not introduce ions or contaminants that could alter enzyme activity or the colorimetric reading. Type I water is ultrapure and has the lowest levels of ions, organic contaminants, and particulates, providing the cleanest and most consistent dilution medium for analytical measurements. This purity minimizes background interference and ensures the dilution accuracy needed for reliable CK results. Tap water contains minerals and chlorine that can affect enzyme reactions and the assay signal, making it unsuitable. Type III water has more impurities than Type I and is generally reserved for non-analytical tasks; it can introduce variability into the measurement. Deionized water, while clean, may still carry trace ions or contaminants depending on the system, so Type I is preferred for critical dilutions to guarantee the highest level of purity and consistency.

In a dilution for an enzymatic assay like CK, the water used must not introduce ions or contaminants that could alter enzyme activity or the colorimetric reading. Type I water is ultrapure and has the lowest levels of ions, organic contaminants, and particulates, providing the cleanest and most consistent dilution medium for analytical measurements. This purity minimizes background interference and ensures the dilution accuracy needed for reliable CK results.

Tap water contains minerals and chlorine that can affect enzyme reactions and the assay signal, making it unsuitable. Type III water has more impurities than Type I and is generally reserved for non-analytical tasks; it can introduce variability into the measurement. Deionized water, while clean, may still carry trace ions or contaminants depending on the system, so Type I is preferred for critical dilutions to guarantee the highest level of purity and consistency.