Which statement best describes the relationship between GFR and CKD stage?

• A. GFR decreases as CKD stage increases
• B. GFR remains constant across CKD stages
• C. GFR increases as CKD stage increases
• D. GFR is unrelated to CKD staging

Answer: (A)

GFR tracks how well the kidneys are filtering blood, and CKD stages reflect how severe that filtration is. As kidney disease progresses, filtration capacity declines, so the GFR numbers fall. Early stages may show normal or near-normal GFR with other signs of kidney damage, while later stages have substantially reduced GFR (often below 15 ml/min/1.73 m2 in very advanced CKD). This inverse relationship means the statement that GFR decreases as CKD stage increases is the best description. The ideas that GFR stays the same, increases, or is unrelated do not fit with how CKD staging is defined and monitored.