Kidney Disease

Kidney Disease is a very broad term, but the major factor observed to determine kidney health is its maximum filtration rate.  In other words how much blood can the kidneys filter per minute?  Over time, Chronic Kidney Disease (CKD) leads to a lessening of capacity, which is rated 1 to 5.

The filtration rate of the kidneys is referred to as the eGFR (which stands for estimated glomerular filtration rate).  The average adult has an eGFR in the order of 100 ml per minute, so the eGFR is also referred to as the percentage of normal kidney function.

As we age, we typically lose 1ml per minute filtration capacity per year.  So a healthy 75 year old may only be expected to have an eGFR of around 50 - 60 ml per minute.  It is important to take this into account when reviewing the Chronic Kidney Disease values below.

Kidney Filtration Rates

Kidney Filtration Rates and therefore kidney function may be estimated from blood creatinine levels, so with a creatinine level (provided in most blood tests from your doctor) your age and your ethnicity, you can get an idea of your kidney health online. 

In reality it is not level of kidney health, but rather the level of Chronic Kidney Disease or CKD which is then calculated.

Kidney Function Calculator

Please click here for an online Kidney Function Calculator, provided by the Renal Association.

Please remember filtration rates vary from one person to the next even when healthy, so there is no absolute value and the online calculator should serve as a guide only.

The 5 Stages of CKD (Chronic Kidney Disease)

• stage 1 is eGFR greater than 90 mls per minute.  However - if all the other kidney tests are normal, there is no CKD and this is only a lower than average normal rate.
• stage 2 is eGFR 60-90 mls per minute. Again there must be some sign of kidney damage.  If all tests are normal, there is no CKD.
• stage 3 is eGFR 30-59 mls per minute.  This is a moderate reduction in kidney function.
• stage 4 is eGFR 15-29 mls per minute is a severe reduction in kidney function.
• stage 5 is eGFR of less than 15 mls per minute, denoting kidney failure, possibly needing dialysis or a kidney transplant.

Acute Kidney disease is mostly restricted to kidney infection or trauma, which themselves may ultimately lead to chronic (or long term) Kidney Disease.  Please see topics below for more discussion on acute kidney infection and acute kidney infection symptoms.