Some doctors use the terms “renal insufficiency” and “renal failure” interchangeably, but there are several different degrees of kidney damage. Some doctors use “renal failure” to refer to the final stages of chronic kidney disease (CKD).

Your kidneys work tirelessly to keep your blood clean and your body healthy. They filter out waste and excess fluid, and they create hormones you need to maintain your bone and blood health. Even though your kidneys are the size of a computer mouse, they do a lot of work.

When your kidneys don’t work correctly, waste and excess fluid can build up in your body. When your kidneys stop working entirely it’s called “kidney failure,” but there are different shades of impairment between fully functioning kidneys and kidneys that aren’t working.

If you have kidney concerns, you may hear lots of different related terms. Many of these terms mean the same thing, while some have small distinctions. If you’re confused about what they mean, read on to learn more.

Renal insufficiency means your kidneys are functioning poorly and need treatment or further diagnosis. A variety of conditions can cause renal insufficiency.

Renal insufficiency implies some degree of kidney failure, but it doesn’t necessarily mean that your kidneys have stopped working.

There are two types of renal insufficiency: acute renal insufficiency, also known as acute kidney injury (AKI), and chronic renal insufficiency, also known as chronic kidney disease (CKD).

Acute kidney injury (AKI)

Doctors may also refer to AKI as “acute renal insufficiency” or “acute renal failure.” AKI develops suddenly, usually over hours or days. It causes waste and fluid to build up in your body and can affect other organs, including your brain and heart.

Many things can cause AKI, including conditions that may cause decreased blood flow to your kidneys, direct kidney damage, kidney cancer, or a blockage in your urinary tract.

Sometimes AKI has no symptoms. When it does, symptoms may include:

AKI is often reversible, and it’s not uncommon, especially among older adults and people in the hospital. Up to 1% of people admitted to the hospital have AKI, which increases to 67% of people in the intensive care unit. Early treatment is key to a good outcome.

Chronic kidney disease (CKD)

Chronic renal insufficiency is also known as chronic kidney disease (CKD). Both terms mean that your kidneys are damaged and can’t filter your blood properly. Doctors consider CKD chronic when your kidneys perform below average for more than 3 months.

According to the Centers for Disease Control and Prevention (CDC), CKD affects 1 in 7 Americans.

Symptoms of CKD can be subtle. You often don’t notice any symptoms until your kidneys are severely damaged.

Doctors sometimes use the terms “renal insufficiency” and “renal failure” interchangeably, but they generally use “renal failure” to describe the fifth and final stage of CKD. This is also known as end stage renal disease (ESRD) or chronic kidney failure.

Renal failure means that your kidneys have stopped, or nearly stopped, working. Symptoms at this stage of CKD may include:

If you show symptoms of renal insufficiency, a healthcare professional may ask you some questions and get a family history. They may also order any of the following tests:

To diagnose renal insufficiency, CKD, or renal failure, doctors estimate your glomerular filtration rate (GFR), or the rate of kidney filtering, by using an estimated GFR (eGFR) test. Your GFR is a marker of your level of kidney function, but GFR is not often directly measured outside a research setting.

A healthcare team calculates your eGFR from your blood creatinine test results and from factors such as your age, race, body size, and sex. If your eGFR number is low, your kidneys may not be working as well as they should.

eGFRWhat it means
90 or aboveYour kidneys are working well.
60–89You may have mild kidney damage, but your kidneys are still working well.
45–59You may have mild to moderate kidney damage. Your kidneys don’t work as well as they should.
30–44You may have moderate to severe kidney damage. Your kidneys don’t work as well as they should.
15–29You may have severe kidney damage. Your kidneys are close to not working at all.
Less than 15You may have the most severe category of kidney damage. Your kidneys are about to stop or have stopped working completely.

An eGFR of 60 or lower for 3 months suggests you have CKD. Doctors may call this condition “chronic renal insufficiency.”

An eGFR of 15 or lower indicates chronic renal failure.

There are several treatments a healthcare professional may try for renal insufficiency. Your treatment will likely depend on whether the renal insufficiency is acute or chronic.

Treatment for AKI usually involves treating the underlying cause. You may need to stay in the hospital. How long you stay will depend on how long it takes to diagnose and treat the underlying cause.

If you have CKD, a healthcare professional may recommend you manage it with medication and lifestyle changes. Experts advise that you:

If you have diabetes, it’s also important to manage your blood glucose levels.

If your kidneys have nearly stopped working or stopped working altogether, a healthcare team may prescribe further options that include:

  • dialysis, which is machine-assisted purifying of your blood
  • continuous renal replacement therapy (CCRT), often for acute failure
  • kidney transplant

Treatment for renal insufficiency is often very successful but depends partially on how you manage it.

The more often you have renal insufficiency, the more likely you are to develop other problems related to it, such as stroke and heart problems.

Even in the case of renal failure, you may live an active life with the right treatment. You may live for many years with the right treatment, even with ESRD.

Summary of terms

Renal insufficiency and renal failure are considered kidney dysfunction.

Acute renal insufficiency, AKI, and acute renal failure all refer to a sudden and often reversible reduction in kidney function.

Chronic renal insufficiency, or CKD, lasts 3 months or more when your kidneys are damaged and can’t filter blood properly.

ESRD and chronic renal failure are terms for the fifth stage of CKD. Your kidneys have nearly stopped working or don’t work at all.

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Your kidneys do a lot of work. They continuously filter wastes and toxins from your blood, maintain your body’s fluid balance, and produce hormones that keep your bones and blood healthy.

When your kidneys don’t work as well as they should, fluid and waste can build up in your body. Doctors call this “renal insufficiency,” and it falls into two categories: acute (short-term) and chronic (long-term). Some doctors may also call this “renal failure,” but they usually reserve the term for severe damage in which the kidneys stop working completely.

The causes and treatments for acute and chronic renal insufficiency can vary. Early treatment is vital, so talk with a healthcare professional immediately if you have symptoms.