Correct! Proteinuria, the presence of increased amounts of protein in the urine, may be the first sign of renal disease. Proteins of low molecular weight (less than 40 kDa) can pass through the glomerular membrane. Albumin, with a molecular weight of 65 kDa, is the largest protein that can normally pass through the barrier. Tamm Horsfall protein, which has a molecular weight of 80 kDa and comprises a third of the protein normally found in the urine, is not found in plasma. Instead, this protein is secreted by the renal tubules and is involved in the formation of casts.