p-Aminohippuric acid is widely used as a diagnostic agent to assess kidney function, specifically effective renal plasma flow (eRPF). When administered intravenously, PAH is almost entirely cleared from the plasma during a single pass through the kidneys. This property arises from PAH’s efficient secretion by the renal tubules, a process that is both active and saturable. Unlike other compounds that are either reabsorbed or partially secreted, PAH is almost exclusively excreted in urine, with minimal amounts remaining in the bloodstream. This near-complete excretion makes PAH an excellent marker for measuring renal plasma flow, which is crucial for assessing overall kidney function. ERPF is a critical determinant of kidney health. It represents the volume of plasma that reaches the renal tubules per unit of time, providing a snapshot of how well blood is being delivered to the kidneys. In clinical practice, this is calculated using the clearance of PAH, defined as the volume of plasma from which PAH is completely removed per minute. This measurement helps in diagnosing conditions where renal blood flow may be compromised, such as renal artery stenosis, chronic kidney disease, or congestive heart failure. The calculated values determined this way can have errors of up to 10%. AkrivisBio’s p-Aminohippuric Acid Assay is a simple sensitive method to measure p-aminohippuric acid in plasma and urine samples.
