Effective Thursday, January 25, the MSU VDL Endocrinology Section will be implementing new methods for select assays. These changes will improve turnaround time, enhance efficiency, and expand the number of days tests are run each week.

Important impacts of these changes on sample submission and test results for the following assays include:

• Vitamin D Profile (20035) and 25-Hydroxyvitamin D (20001): The required sample type is serum ONLY. Reference intervals will be impacted by the change in method and an updated reference document will be posted. Please note that the reference intervals on reports will be different.

• IGF-1 (20005): Results will be reported in a new unit (ng/mL). Results were previously reported in nmol/L. The change in method and units will also impact reference intervals, which will be reflected on reports.

• Total T4 for non-canine, non-feline thyroid profiles (20015, 20016): Measurement of total T4 will no longer be run by radioimmunoassay (RIA) and will be transitioned to a chemiluminescent assay. An updated laboratory-generated reference interval is being developed for equines and will be available when completed. This change helps us to both improve turnaround time for these tests and continue to reduce our radioactive waste.

Please contact the laboratory at 517.353.1683 with any questions about these changes.