Understanding CKD Staging

How is CKD staged?

CKD is staged based on the estimated Glomerular Filtration Rate (eGFR), which indicates how effectively the kidneys filter waste. Clinicians use specific numeric cutoffs to determine the level of impairment, ranging from normal function to kidney failure.

The primary logic for a CKD diagnosis involves an eGFR of less than 60 mL/min/1.73m² that persists for 3 months or longer, often accompanied by other markers of structural or functional damage.

Example of Staging Analysis

Consider a sample patient who receives an eGFR lab result of 40 mL/min/1.73m².

Staging Steps:

• Value Identified: Patient's eGFR is measured at 40.
• Persistence Check: The value is confirmed to be stable over a 90-day period.
• Range Matching: The value falls within the 30-44 cutoff range.
• Final Classification: The patient is classified as Stage 3b (Moderate to Severe CKD).

CKD Stages Overview

• Stage 1 (eGFR 90+): Kidney damage with normal function.
• Stage 2 (eGFR 60-89): Kidney damage with a mild decrease in function.
• Stage 3a (eGFR 45-59): Mild to moderate decrease in kidney function.
• Stage 3b (eGFR 30-44): Moderate to severe decrease in kidney function.
• Stage 4 (eGFR 15-29): Severe decrease in kidney function.
• Stage 5 (eGFR < 15): Kidney failure, often requiring dialysis or transplant.

Disclaimer: This content is provided for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

Frequently Asked Questions

What is eGFR? It stands for estimated Glomerular Filtration Rate, a calculation using blood creatinine levels, age, and sex to estimate how well your kidneys are working.

Is Stage 1 serious? While eGFR is normal in Stage 1, the presence of kidney damage (like protein in urine) is an important indicator to begin managing blood pressure and lifestyle to prevent progression.

Can kidney function improve? While chronic damage is often permanent, addressing the underlying cause (like diabetes or hypertension) can stabilize kidney function and sometimes result in a modest eGFR increase.