A critically low glomerular filtration rate (GFR) indicates severe kidney dysfunction. GFR below 15 mL/min/1.73 m² signifies kidney failure requiring urgent medical attention. Levels persistently below 60 mL/min/1.73 m² for three or more months signal chronic kidney disease.
Understanding GFR
The glomerular filtration rate (GFR) measures how well your kidneys filter blood. It's a crucial indicator of kidney health. A normal GFR varies based on age, sex, and body size; young adults typically have a GFR around 120 mL/min/1.73 m², while it naturally decreases with age.
- Normal GFR: Generally above 90 mL/min/1.73 m² (this can vary based on age and other factors).
- Chronic Kidney Disease (CKD): A GFR consistently below 60 mL/min/1.73 m² for three months or longer.
- Kidney Failure: A GFR below 15 mL/min/1.73 m². This is a medical emergency requiring immediate intervention, often dialysis.
The reference materials highlight that various equations exist to estimate GFR, often using serum creatinine levels. However, these estimations are not always accurate, especially in critically ill patients where direct measurement is often more reliable. The accuracy of GFR estimation also depends on the precision of the serum creatinine assay.
Several factors influence GFR:
- Age: GFR naturally declines with age.
- Sex: There can be slight differences between genders.
- Muscle Mass: Lower muscle mass (as in the elderly) can lead to lower creatinine levels and potentially inaccurate GFR estimates.
- Health Conditions: Various diseases can impact kidney function.
While estimated GFR (eGFR) is commonly used, it's vital to remember that it's an estimate. In critical care settings, direct measurement is preferred for accurate assessment.
