Stability test of six enzymes for internal quality control

Area of Science:

• Clinical Chemistry
• Biochemistry
• Enzymology

Background:

• Daily quality control is crucial for accurate enzyme activity concentration determination in clinical chemistry.
• Commercially available control sera are expensive, necessitating simpler, cheaper alternatives.

Purpose of the Study:

• To develop and evaluate a simple, reliable, and inexpensive method for the quality control of enzyme determinations.
• To assess the stability and reliability of enzyme-albumin solutions as a substitute for commercial control sera.

Main Methods:

• Commercially available enzymes were suspended in albumin solution and stored at 4°C or -20°C.
• Catalytic activities of enzyme-albumin solutions were compared weekly for 10 months with freshly reconstituted control sera.
• Enzymes analyzed included aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatine kinase, gamma-glutamyltransferase, and alpha-amylase.

Main Results:

• Enzyme-albumin solutions demonstrated stability and reliability comparable to commercial control sera for most enzymes tested over 10 months.
• The catalytic activity concentration of creatine kinase showed a slow decrease over the 10-month period.
• The enzyme solutions responded similarly to commercial test sera regarding changes in reaction conditions.

Conclusions:

• Enzyme-albumin solutions are a viable, cost-effective alternative for daily quality control of enzyme determinations in clinical chemistry.
• This method provides a reliable and affordable approach to ensure accuracy in enzyme activity measurements.
• Further investigation into the stability of creatine kinase in these solutions may be warranted.