Also called clearance papers. the official papers certifying this.
10.
Medicine/Medical. a test of the excretory function of the kidneys based on the volume of blood that is cleared of a specific substance per minute by renal excretion.
1560s, "action of clearing," from clear (v.) + -ance. Meaning "a clear space" is from 1788. Meaning "approval, permission" (especially to land or take off an aircraft) is from 1944, American English; national security sense recorded from 1948. Clearance sale attested by 1843.
clearance in Medicine
clearance clear·ance (klēr'əns) n. The removal of a substance from the blood, expressed as the volume of blood or plasma cleared of the substance per unit time.