Glomerular filtration rate (GFR) scan - Preparation Requirements
TOTAL DURATION OF STUDY:
Excessive intake of drinks containing caffeine including tea, coffee and Coke should be avoided after 10 pm the night before the test because of their diuretic effect (Clomius et al, 1979). Protein load may increase GFR (Wilkinson et al, 1991) and it is recommended to avoid high protein meals before the study. Since neither carbohydrate nor fat loads affect GFR, a light meal, low in protein would optimise accuracy and reproducibility. (Levine et al, 1986). A light breakfast is recommended. If the test straddles the lunch period then a light lunch e.g. sandwiches can be taken.
Exercise has been shown to have a variable effect on GFR (Merrill et al, 1948, Kachadorian et al, 1970, Wilkinson et al, 1991). Strict bed rest is unnecessary, but some restriction of activity is necessary for good reproducibility.