PHENOLSULFONPHTHALEIN TEST

also called Psp Test, clinical procedure for the estimation of overall blood flow through the kidney; the test is used only infrequently now. A specific dose of the PSP dye is injected intravenously, and its recovery in the urine is measured at successive 15-, 30-, 60-, and 120-minute intervals. The kidney secretes 80 percent of the PSP dye, the liver the remaining 20 percent. The recovery value at 15 minutes after injection (normally about 25-35 percent) is the most significant diagnostically, since even a damaged kidney may be able to remove the PSP dye from circulation given a longer time to do so. PSP excretion is decreased in most chronic kidney diseases and may be increased in some liver disorders. See also kidney function test.