Diagnosis of Chronic Kidney Failure

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Blood collection tube

Chronic kidney disease or chronic kidney failure is diagnosed through blood tests that measure creatinine and urea, or BUN, levels as these are the main toxins eliminated by our kidneys. Urine is also analysed to discover the exact volume and composition of urinary output. These results are used to calculate the overall percentage of kidney function (glomerular filtration rate, GFR) which subsequently determines the degree of kidney failure.

stage description glomerular filtration rate (GFR)
1 Kidney damage with normal GF > 90 mL/min
2 Kidney damage with mild loss of GF 60–89 mL/min
3 Moderate loss of GF 30–59 mL/min
4 Severe loss of GF 15–29 mL/min
5 Kidney failure < 15 mL/min or dialysis


Magnetic Resonance Imaging or MRI machine

Additionally, an ultrasound is taken and, in some cases, a CT scan or MRI to determine the kidneys’ size and shape. In other instances, a kidney biopsy may also be carried out.

It is essential to diagnose kidney disease in its early stages (1 to 3) in order to prevent the loss of kidney function and onset of cardiovascular complications, thus preserving function for several years and delaying the need to resort to dialysis. Most individuals do not notice any particular symptoms; they may feel a little tired or have swollen legs.

It is important to follow the nephrologist’s indications when first diagnosed with kidney disease so as to reduce the rate of kidney function deterioration, e.g., reduce salt intake, lose weight or follow an appropriate diet, amongst others.

Substantiated information by:

Anna Yuguero
Bárbara Romano Andrioni
Manel Vera Rivera
Marta Quintela Martínez
María Teresa López Alonso
Montserrat Monereo Font
Ángeles Mayordomo Sanz

Published: 20 February 2018
Updated: 20 February 2018

The donations that can be done through this webpage are exclusively for the benefit of Hospital Clínic of Barcelona through Fundació Clínic per a la Recerca Biomèdica and not for BBVA Foundation, entity that collaborates with the project of PortalClínic.


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