High creatinine levels commonly occur due to changes to kidney function, increased protein intake, or from taking creatine supplements. It can also happen due to more serious problems, like a kidney infection, diabetic ketoacidosis or high blood pressure.

Creatinine is a substance that is produced by the muscles and eliminated by the kidneys through urine. This is why creatinine levels can be tested in both the urine and the blood. Normal blood creatinine levels will vary depending on several factors, like gender and lab reference ranges. The normal creatinine range for women is 0.6 to 1.2 mg/dL, and 0.7 to 1.3 mg/dL for men.

You should worry about high creatinine levels if your creatinine measures above these ranges and you notice symptoms like fatigue, nausea and vomiting and swelling, as these can be a signs of a health condition that requires treatment.

What causes high creatinine?

Creatinine can become elevated as a result of many situations, such as:

1. Excessive physical activity

Working out intensely and frequently can lead to increased creatinine levels in the blood. This increase is not related to changes in kidney function, but rather, is a consequence of increased muscle mass.

What to do: Creatinine is a substance that is produced by the muscles. When elevated creatinine levels are related to increased muscle mass, treatment is not necessary.

2. Dehydration

Dehydration is associated with decreased water volume in the body, which concentrates the urine in the kidneys. Concentrated urine can also be more difficult to filter, leading to increase creatinine levels in the urine and blood.

What to do: You should increase your water and tea intake, making sure to divide your intake throughout the day. You should also eat fresh fruits and vegetables, as they are also rich in water content. In some cases, you may need to replenish your electrolytes, which can be done with a home saline solution made with water, sugar and salt.

3. Increased protein intake

Athletes or people that work out often are more likely to consume higher amounts of protein, like meat, eggs, and fish, to improve their physical performance. This causes the muscles to trigger the use of creatine phosphate, which is an enzyme that produces creatinine as an end-product, leading to increased levels in the blood.

What to do: You should eat a maximum of 1.2 g of protein per kilogram of body weight per day. Someone who weighs 60 kg, for example, should eat a maximum of 72 g of protein per day. Ideally, you should see a registered dietitian to evaluate your general health status and nutritional necessities, so that a personalized eating plan can be made. Read more about high protein foods and how to incorporate them appropriately into your diet.

4. Excessive creatine supplements

Creatine is converted into creatinine in the body, and therefore ingesting too many creatine supplements can lead to increased creatinine levels in the blood.

What to do: You are advised to speak to your doctor or dietitian about the recommended creatine dose you should supplement with. Dosing will vary depending on your health goals. Learn more about creatinine supplementation, when to use it and how to take it safely.

5. High blood pressure

High blood pressure can damage your blood vessels, which can lead to decreased systemic circulation. This can decrease the kidney’s ability to filter the blood, resulting in elevated creatinine in the blood. Understand the symptoms of high blood pressure that can occur if left untreated.

What to do: To treat high blood pressure, the doctor may prescribe medications like diuretics or vasodilators. You should also exercise regularly and eat a healthy, balanced diet. There are also home home remedies for high blood pressure that you can use to complement any recommended medical treatment.

Check out the high blood pressure diet that can help you to regulate high blood pressure.

6. Pre-eclampsia

Pre-eclampsia is a pregnancy complication that is associated which changes to the blood vessels, decreased circulation and increased blood pressure. It can damage the kidneys and cause increased creatinine levels, putting the mother and baby both as risk.

What to do: You are advised to drink plenty of fluids and reduce your salt intake. Some women may require admission to the hospital for monitoring and IV blood pressure medication.

7. Kidney infections

Kidney infections can be caused by bacteria, viruses or fungi that are naturally present in the urinary tract. High creatinine levels generally occur with chronic infections, when treatment is not effective and microorganisms remain in the kidneys and cause damage. Learn more about kidney symptoms that may signal a problem.

What to do: Kidney infections and related symptoms can be treated with medications like analgesics, anti-inflammatories and antibiotics. Cranberry juice is often recommended during treatment, because it is rich in bioactive antioxidants that prevent the build-up of bacteria in the urinary tract.

Read more about a renal diet that you can initiate to promote optimal kidney function.

8. Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) occurs when blood sugar levels are high and left untreated. It can lead to complications like changes to kidney function, resulting in high creatinine levels.

What to do: Treatment will depend on the presenting symptoms. The doctor may prescribe insulin, and will likely recommend a low-fat diet with decreased simple carbs. Read more about the diabetic diet that is recommended to manage this condition.

9. Kidney failure

Kidney failure is characterized by a change to kidney function in which the kidneys lose their ability to filter the blood efficiently. This can lead to an accumulation of creatinine in the blood.

Kidney failure can occur due to decreased circulation (from high blood pressure for example), dehydration, excessive supplement use, or from frequent medication use.

What to do: To treat kidney failure, the doctor may prescribe anti-hypertensives, like furosemide, spironolactone, minoxidil or hydralazine. While treating, the patient should also opt for a diet that is low in protein, salt, phosphorus and potassium. In life-threatening cases, dialysis or even a kidney transplant may be necessary.

When to worry about creatinine levels

Creatinine is a natural by-product created by the body after wear and tear of the muscles. It is typically excreted in the urine, but can start to accumulate in the blood if the kidneys are not working properly. Having high creatinine is not a problem in itself, however it may mean that there is another health issue going on, particularly one associated with kidney functioning.

Higher creatinine levels may be associated with symptoms, as listed below. If you experience these symptoms, you should consult your doctor for assessment.

Common symptoms

When creatinine levels are above the normal values, it is possible to experience symptoms like:

Fatigue
Loss of appetite
Nausea and vomiting
Shortness of breath
Itching
Leg and arm swelling

These symptoms are more frequent in people who have extremely high creatinine levels, however they can be present in people with a family history of kidney problems, in people over 50, and in those with chronic health issues like diabetes and high blood pressure.

Confirming a diagnosis

To diagnosis high creatinine, the doctor will first evaluate the presenting signs and symptoms and assess your general health status.

The doctor will order a blood test to investigate your creatinine levels. High levels may prompt the doctor to also order a 24 hour urine test, to determine whether the high creatinine is related to a kidney filtering problem.

Kidney function can also be assessed through creatinine clearance tests. Learn more about what this exam tests and how it can be useful to reach a diagnosis.