Author`s Reply.

To the Editor,

NP-40 and Tween-20 are two detergents for cell lysis and protein extraction that have hydrophobic–hydrophilic interactions among molecules in biological specimens. They are used to lyse cells to release soluble proteins that are present in a cell and are used in both immunoassay and electrophoresis procedures (1,2). We measured salusin-β levels using ELISA in serum samples (3). It is well known that serum comes from the liquid portion of the blood by removing cells. Therefore, the use of these two detergents played no role in our study, similar to that observed in other protein analysis studies with serum samples.