Glomerular Filtration Rate ✅ Flashcards
What is GFR a measure of?
Renal function
What is the reference solute for GFR estimation?
Inulin
What is the limitation of using inulin as the reference solute for GFR estimation?
It is mainly used as a research tool
How is GFR measured in fracture?
Using radiopharmaceuticals
Give 3 radiopharmaceutics that can be used in the measurement of GFR?
- 99m Tc-DTPA
- 125I-iothalamate
- 51 Cr-EDTA
What are the advantages of isotopic methods of measuring GFR?
They do not require timed urine collection
What is the limitation of using radiopharmaceuticals to measure GFR?
They are too complex for routine clinical use
What is the result of radiopharmaceuticals being too complex for routine clinical use?
Creatinine is used as a surrogate marker for renal function
What is the limitation of using creatinine as a surrogate marker for renal function?
- Not an early indicator of renal damage
- Varies depending on a number of factors
What factors does serum creatinine vary depending on?
- Age
- Muscle mass
- Nutritional status
When might serum creatinine be inappropriately low?
- Malnourished children
- Those with major amputation
What has been used to mitigate against factors affecting creatinine?
Formulas for calculating GFR to correct for body size
Give an example of a formula that corrects serum creatinine for body size?
Modified Schwartz formula
What is the modified Schwartz formula?
K x height (cm) / plasma creatinine
K = constant
What is measure when testing for renal function?
Serum electrolytes
