Enzyme analysis includes some of the most frequently performed tests in clinical laboratories, due to the diverse and critical biochemical roles these molecules play in human pathophysiology. As such, the laboratories need access to a supply of specific clinical reference materials, which are designed and used for calibrating instrument systems, validating new clinical assays, instrumentation, and a host of similar products. Access to independent validation tools is vital for determining an enzyme method’s accuracy, linearity, sensitivity, range, and other performance characteristics, as required under several current regulatory mandates.
Based on the suggestions from clinical lab professionals, researchers, and regulatory agencies, enzyme verification materials should contain the following product attributes:
Liquid-stable, protein-based matrix
A liquid-stable, protein-based format helps eliminate not only reconstitution errors but also matrix variations commonly experienced with lyophilized and serum-based products.
A multilevel or analyte product format helps save time, money, and expenses with numerous departments in a facility.
As clinical reference materials are not used daily, it is important to have products with extended shelf life and open vial stability claims, and that withstand multiple freeze–thaw events.
With laboratory storage space in demand, it is advantageous to package products in ergonomically designed kits for convenient storage. Materials packaged in dropper vials are easy to use and less prone to deterioration. Ideally, reference material should contain fill volumes enough to cover multiple testing events and any unexpected system troubleshooting necessities.
Customer support and product documentation
In the current regulatory environment, it is important to select vendors whose product(s) have the necessary FDA 510(k) clearance, when applicable, and are able to supply various product support documentation (i.e., instructions for use, safety data sheets, value assignment sheets, etc.) quickly upon request. Investigate what ancillary services are available from vendors to further support product performance and assist the laboratory, including but not limited to, data reduction services, test report generation and printing, online and phone support, etc.
Product Design Format
Clinical reference material formulations should incorporate critical blends of specific biologicals, along with highly purified raw material components, to produce bio-based materials that minimize matrix variations. In addition, they should also incorporate the necessary target concentration designs to address the current regulatory requirements for calibration verification materials. For example, product formulation should include at least one set point for each enzyme within the normal range.