# eGFR (CKD-EPI)

Source: https://synapse-lifestyle.com/en/reference-guide/biomarkers/egfr

Unit: mL/min/1.73m²

## What is eGFR (CKD-EPI)?

eGFR is an estimate of how well your kidneys filter your blood. It's calculated from your creatinine, age and sex. Well-functioning kidneys clear out waste products and keep your fluid balance in order. A healthy value is reassuring; higher is better here.

## Clinical frame

Calculation:

```
eGFR computed with the race-free CKD-EPI 2021 equation from serum creatinine, age and sex (mL/min/1.73 m²)
```

The **glomerular filtration rate** is the best overall measure of kidney function, but cannot be measured directly. Synapse estimates it with the race-free CKD-EPI 2021 equation from serum creatinine, age and sex. Age and sex serve as a surrogate for muscle mass, which makes the estimate more accurate than creatinine alone [1] [2].

An eGFR below 60 that persists for at least three months defines, together with albuminuria, **chronic kidney disease**. Higher values count as kidney damage only with additional signs such as albuminuria. Interpret the eGFR together with the ACR in the KDIGO risk matrix. A lower eGFR is gradually associated with death, infarction, stroke and heart failure [2] [3].

Genetic studies show that mildly to moderately reduced kidney function **contributes causally** to coronary disease [3]. The estimate is valid only in a stable state and is distorted by abnormal muscle mass, extreme protein intake, cirrhosis and some medicines. In case of doubt, combining it with cystatin C gives a more accurate picture [1].

## What moves this value?

The value falls slightly over the years. Dehydration, blood pressure and muscle mass can temporarily affect a measurement.

Drinking enough, a healthy blood pressure and not too much salt support your kidneys. Discuss a falling trend calmly with your doctor.

Developed and reviewed with the Synapse [medical advisory board](https://synapse-lifestyle.com/en/advisory-board).

## References

1. Levey, A. S., Grams, M. E. & Inker, L. A. Uses of GFR and Albuminuria Level in Acute and Chronic Kidney Disease. N Engl J Med 386, 2120–2128 (2022). https://doi.org/10.1056/NEJMra2201153
2. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int 105, S117–S314 (2024). https://doi.org/10.1016/j.kint.2023.10.018
3. Gaziano, L. et al. Mild-to-Moderate Kidney Dysfunction and Cardiovascular Disease: Observational and Mendelian Randomization Analyses. Circulation 146, 1507–1517 (2022). https://doi.org/10.1161/CIRCULATIONAHA.122.060700

- [Read more in the reference guide](https://synapse-lifestyle.com/en/reference-guide/heart#Consequence-CSKidney-FCKDEPI)
- [All biomarkers in the guide](https://synapse-lifestyle.com/en/reference-guide#biomarkers)

The colour zones are personal: they depend on age, sex, risk and history, and appear in the patient's own report.

Insights to discuss with the patient, not a diagnostic instrument.