In the Original Investigation entitled “A New Panel-Estimated GFR, Including β2-Microglobulin and β-Trace Protein and Not Including Race, Developed in a Diverse Population” that appeared in the May 2021 issue of AJKD,1 there was an error regarding the source of the β-Trace Protein (BTP) and β2-Microglobulin (B2M) samples. The samples were reported as being measured in serum; however, the samples were measured in EDTA plasma.