CD79A and chronic kidney disease: Log transformation of the values for serum levels of Gd-IgA1-specific IgG or Gd-IgA1-specific IgA did not normalize the distributions of the data (Fig 1B and 1C), as they failed to pass the D’Agostino and Pearson normality test.[18] Using either the raw-data distributions or log transformation of the data, the serum levels of Gd-IgA1-specific IgG in the IgAN and CKD cohorts exhibited a significant positive skew.