process öf glomerular filtration TO measure creatinineclearance. patienr's urine output is collectad for 24-hrs Plasma creatinlne concentrailon

mlnute) The clearance (vöurme/time) can then be calculated by deterrmining the volume öf ptasma which contatains UV/mmol/mlnute öf the sustanca, that is whera P(mmol/1) the plasma concentration to summarlza formula for clearance. Clearancs = GFR it the substance is fraely fillsrad Since the rala of glomerular filtration depends broadly on the number of glomerull (hence nephrons) present, the amount öf renal damage and therefore tne severity öf renal fallure can be assessed by measuring GFR Factors influencing GFK. Increäse - (a) Pre-renal factors - dehydration, hypotension, severe cardiac failure. (b) Renal damaga (c) Urtnary tract obaiructlon (d) Low-proisin diel (e) Drugs - AGE Inhlbliors, NSAIDS Increase-(a) High proteln dievmeal. (b) Eaily diabetes (c) Pregnancy (d) Growth hormone (a) Acrornagaly, (f) Dlumal Variation (increasedin afternoon) Plasnma creatinine and creatinine clearance Creatinine is the moat useful endogenous meiaoolism for cosessing glomeruar function, and is virlually all excrated by the kidneys, mainly by process öf glomerular filtration to measure creatinineclearance. patienr's urine output is collectad for 24-hrs Plasma creatinlne concentrailon (Pcr mmol/1) and urlne creatinine concentratIon (Ucr mmov 1) are measured and the duration of urinecollection and volume collected are recorded Normal creatine clearance is about 120 mvminute (varias with body size) Creatinine Clearänce (mvmin) - Plasma creatinine concentration -Normal por is O O4-011 mmoV1. Factors influencing plasma creatintine concentration - Increase- (a) Raduced GFR (b] Increased creatninea load .(increäsed muscle mass) (c) Reduced tubular creatinine secretion due to drugs (e,g trlmethoptim.