Differences in reaction specificity toward lipoprotein X and abnormal LDL among 6 homogeneous assays for LDL-cholesterol

The homogeneous LDL-C assays showed differential reactivity toward Lp-X and abnormal LDL. Our findings enable accurate interpretation of the LDL-C values in these homogeneous assays, and suggest that these methods should be improved to distinguish between normal LDL and abnormal LDL or Lp-X.