Conditions for Solubilization of Tamm–Horsfall Protein/Uromodulin in Human Urine and Establishment of a Sensitive and Accurate Enzyme-Linked Immunosorbent Assay (ELISA) Method

Tamm–Horsfall protein (THP), also referred to as uromodulin, is a major glycoprotein produced by kidney cells. The level of THP in urine is an indicator of renal function. THP levels are difficult to quantify accurately, because the protein forms aggregates in the pH and ion concentrations found in urine. Here, we describe conditions by which THP can be solubilized and kept soluble during measurement using Triton X-100, EDTA, and alkaline pH. Establishing conditions for precise quantification of THP by enzyme-linked immunosorbent assay (ELISA) will aid in studying the functions of THP.