Financial service providers market many different products as being available for nominal fees. A nominal fee is a payment or purchase price like any other fee. However, the use of the work nominal implies that the fee is small in comparison to the true value of what you can purchase with it.
Creatinine clearance in a healthy young person is about 125 milliliters per minute -- meaning each minute, that person's kidneys clear 125 mL of blood free of creatinine. The GFR can vary depending on age, sex, and size. Generally, the creatinine clearance is a good estimation of the glomerular filtration rate.
GFR can be estimated using a single blood level of creatinine, which your doctor enters into a formula. Different formulas are available, which take into account age, sex, and sometimes weight and ethnicity. The higher the blood creatinine level, the lower the estimated GFR and creatinine clearance.