PAH is used to measure?: (A) Extracellular fluid, (B) Glomerular filtration rate, (C) Renal plasma flow, (D) Plasma value
Answer is C. Ans. is'c'i.e., Renal plasma flow [Rel Ganong 248/e p, 678-679)A substance which closely satisfies this description is para-aminohippuric acid (PAH), Therefore,PAH is used to measure renal plasma flow.The PAH clearance ln a normal adult lc about 625 mV minute. That's a measure of effective renal plasma flow (ERPF).PAH is only 90% excreted in the urine in a single passage through the kidney, i.e., its extraction ratio is 0.9 (90%).