Article Critique on Method evaluation study of a new generation of vitamin D essays.
Write a critical review of the article: Enko D, Kriegshauser G, Stolba R, et al. Method evaluation study of a new
generation of vitamin D assays. Biochemia Medica.(2015) 25(2): pp. 203-12. . Note the following: The
reference range for vitamin D is approximately 10-65 ng/mL. CLIA has no TEa for vitamin D measurements. It
can be taken as 3x the method’s standard deviation, a general practice for immunoassays; however, we do not
know the standard deviation for these methods. A study by Stocki et al. has been used by other studies to
evaluate SEa and REa of total vitamin D assays. These authors use a 5% limit for bias and a 10% limit for CV.
Use this benchmark to determine total error allowable for vitamin D assays. Source: Stocki D, Sluss PM,
Thierpont LM. Specifications for trueness and precision of a reference measurement system for serum/plasma
25-hydroxyvitamin D analysis. Clin Chem Acta. (2009)408: pp 8-13.
Your critique must answer the following questions:
- Keeping in mind that this study was not meant to be either a validation or verification of manufacturer’s
claims what is missing from this study? - Was 3-epi-25-hydroxy vitamin D a confounder in this study?
- Were sample collection and processing appropriate?
- The authors conclude that precision of all four assays is acceptable because within run and between run
precision were each below 20%. Are there any concerns with their precision study benchmarks and
interpretation? - The authors conclude that the new IDS-iSYS and ORGENTEC 25(OH)D assays are suitable for measuring
total vitamin D in clinical laboratories. Would you adopt the ORGENTEC 25(OH)D assay for your laboratory?
Explain why or why not. - Do you agree that this study shows that lack of standardization is the solution to solving the intraassay bias
problem seen with 25(OH)D assays? Why or why not