Representative SDS-PAGE separation of 17 000×g, 210 000×g, and TCA fractions of three urine specimens (1, 2, 3), demonstrating small differences in total protein abundance among different urine specimens, and preferential fractionation of albumin (●) and uromodulin (▶) in the 17 000×g fraction, enabling improved detection of the remaining urinary proteins. The majority of albumin and uromodulin appears to sediment at 17 000×g, suggesting that they exist in high-molecular-weight complexes, consistent with uromodulin's ability to polymerize in urine.