Hemodialysis Vascular Access Creation in Patients Switching From Peritoneal Dialysis to Hemodialysis: A Population-Based Retrospective Cohort (original) (raw)

using high-throughput mass spectrometry assays developed and validated in our laboratory. 2-4 More recently, the National Institute of Standards and Technology (NIST) developed a candidate reference method procedure and used it to quantify 24,25(OH) 2 D 3 concentration in their Standard Reference Material (SRM) 972a. 5 When we used our assay to quantify 24,25(OH) 2 D 3 in SRM 972a, we noticed that our observed concentrations were higher than those reported by NIST. Using this information, we recalibrated our assay, ran the reference materials again, and obtained concentrations that agreed with those certified for SRM 972a. From these data, we determined that the 24,25(OH) 2 D 3 concentrations published in our report 1 should be divided by a factor of 2.0 to compare our data with those generated in other laboratories for which results are calibrated to SRM 972a. This calibration does not affect the conclusions of our article, including the association of estimated glomerular filtration rate with circulating 24,25(OH) 2 D 3 concentration or the correlations of demographic factors, clinical parameters, and regulatory hormones with 24,25(OH) 2 D 3 concentration. Our experience is a testament to the importance of standardization programs in the proper interpretation and comparison of data from many laboratories over time.