What is Creatinine? What Does Low and High Creatinine Mean?

by Abbas Jahangir · June 24, 2024

People often hear the word creatinine when they have a blood test. The result of this blood test is the creatinine level, by which we can interpret the amount of muscle a person has and the health status of their kidneys. Apart from blood tests, creatinine levels can also be checked using 24-hour urine samples.

What is Creatinine?

A compound called creatine is produced in the muscles, and the product resulting from the breakdown of this compound is called creatinine. The level of creatinine in the blood may vary depending on certain factors. These factors include age, gender and muscle mass. The kidneys filter this waste product, which is broken down in the muscles, and remove it from the body with urine. Meanwhile, a balance occurs between production and excretion in the body and the creatinine level is maintained at the required levels.

If the kidneys do not work properly, the amount in the blood or urine is higher than it should be. Some different situations also affect creatinine levels: diet and a person’s physical activity level.

Creatinine levels give very important information about a person’s health. Therefore, it is of great importance to check its levels in blood or urine tests.

Although it is generally produced in the body from the muscles, it can also be produced, albeit in small amounts, from amino acids taken with the diet. Since its production is related to muscles, creatinine levels are high in people with a high percentage of muscle, while creatinine levels are low in people who are old, weak and have a low muscle percentage. Creatine is used by muscles to produce energy.

A little-known feature of creatine is that, although it is known as a waste product of the muscles, it can play a role in the fight against diseases by stopping the growth of bacteria in the body.

Blood Creatinine Test

Creatinine levels can be checked from blood tests or urine analysis. The process of measuring the amount of creatinine in the bloodstream, measured with the help of blood tests, is called serum creatinine, and the process of measuring creatinine levels in urine is called creatinine clearance.

Serum Creatinine: Allows us to check the levels of creatinine in the bloodstream. Creatinine levels generally give us an idea about kidney functions. It helps define the glomerular filtration rate (GFR), one of the important parameters that gives information about kidney health. GFR is a calculation process made using some values of a specific patient. These values can be counted as age, gender, weight as well as creatinine. Since creatinine levels vary according to muscle levels, creatinine levels in women are lower than in men. The creatinine reference range may be between 0.6-1.2mg/dL in men and 0.5-1.1mg/dL in women.

Creatinine Clearance: It is a method that allows us to determine how much of the amount of creatinine produced in the muscles is excreted from the kidneys with the help of urine. Thanks to this method, it can be determined how properly the kidneys filter waste. Urine test and blood test are used together in this method.

In some cases, it is recommended that the patient perform these tests frequently and have their values checked regularly.

People with diabetes
Those who generally have high blood pressure
People with acute kidney injury
People with cardiovascular diseases
Those who experience conditions that can negatively affect the kidneys (kidney stones, enlarged prostate, lupus)
People with a family history of severe hereditary kidney damage
People who have used or continue to use drugs that negatively affect the kidneys or tire the kidneys, such as lithium, non-steroidal anti-inflammatory drugs, chemotherapy drugs, cephalosporin antibiotics, for a long time should have these tests done regularly at regular intervals.

In Which Ranges of Creatinine Levels Are Risk Factors for Human Health?

The units of measurement for creatinine levels are known as milligrams per deciliter (mg/dL) or micromoles per liter. The required range of creatinine in the blood is said to be 0.84-1.21 milligrams per deciliter (74.3-107 micromoles per liter). A GFR level of 60 or above is considered normal, while GFR levels below 60 may indicate a disease in the kidneys. A GFR of 15 or lower is defined as kidney failure.

High Creatinine

When creatinine levels in the blood are seen to increase, it is understood that the production of creatinine in the muscles or any part of the body has increased. Factors that can cause increased creatinine in the blood include:

Chronic Kidney Disease: These are some negative conditions that may cause the kidneys to disrupt their processes such as excretion and filtering. Examples of these conditions include kidney failure , kidney infection, and decreased blood flow to the kidneys.

Urinary Tract Obstruction: These are some negative conditions in which the urine flow is blocked. (Hydronephrosis) These conditions may be an enlarged prostate or kidney stones.

Water Loss: Kidney damage that may occur as a result of severe dehydration. Low blood pressure resulting from this severe dehydration can also negatively affect the kidneys.

Excessive Protein Consumption: Excessive protein consumption, taking external protein supplements, and frequent consumption of cooked meat containing large amounts of creatinine may also cause an increase in creatinine levels in the blood.

Exercising Intensively: When people exercise intensively, working muscles create creatinine much faster than normal levels. Thus, creatinine levels in the blood also increase.

Some Medicines: Some antibiotics such as trimethoprim and drugs in the H2 blocker group such as cimetidine can be given as examples.

Some autoimmune diseases (For example, Lupus)
Goodpasture syndrome
gout
Rhabdomyolysis (breakdown of muscle fibers)
muscular dystrophy
Blood loss due to injury
Overactive thyroid gland
Congestive heart failure
diabetes mellitus
Problems such as seizures caused by eclampsia during pregnancy or high blood pressure caused by preeclampsia
Glomerulonephritis, which is inflammation of the glomerulus.

High levels of creatinine in the blood indicate that there is a problem in the functioning of the kidneys and that the creatinine formed in the body cannot be properly filtered by the kidneys and excreted in the urine. While high levels of creatinine in infants raise suspicion of bacteremia, it may raise the risk of prostate cancer or kidney cancer in adult men.

Symptoms of High Creatinine

Nausea in the stomach
Vomiting
Fatigue, weakness
Loss of appetite and resulting weight loss
Frequent urination,
Painful-bloody urine
high blood pressure levels
Pain in the chest,
cramps in muscles
Edema
Having trouble breathing
Dryness on the skin

How to Lower Creatinine High?

In order to reduce creatinine levels, the first thing to do is to determine the cause of the elevation and follow a path according to this determination. This problem needs to be treated. In addition, it is also very important to make differences in nutrition. Limiting the consumption of red meat, which is high in protein, and reducing high-tempo, challenging exercises also help.

Low Creatinine

Creatinine levels below normal may indicate that the liver or muscles are not working as they should.

Why Does Creatinine Drop?

Low Muscle Mass: Age, gender, and some diseases may play a role among the causes of low muscle mass. Examples of these diseases are myasthenia gravis and muscular dystrophy. Excessive weight loss also causes muscle levels to decrease.

Pregnancy: Low creatinine may occur as a result of increased urine production and increased water loss during pregnancy, but this situation ends with the end of pregnancy.

Liver Problems: Due to the production of creatinine in the liver, low creatinine levels may occur with impaired liver function because creatinine cannot be produced at normal levels. In chronic liver disease, creatine production can decrease by 50%.

Malnutrition: It is known that creatine is not only produced in the body but also taken from food, so nutrition is very important.

Symptoms of Low Creatinine

Weakness in muscles
exercise difficulty
Pain in the muscles and therefore decreased mobility
If the underlying cause of low creatinine is liver disease, symptoms may include fatigue, nausea, jaundice, abdominal pain, swelling, bloody or tar-colored stools.
If the underlying cause is nutritional problems, symptoms such as dizziness and weight loss are observed.

Low Creatinine Treatment

After test results show that creatinine levels are low, other tests are performed to prevent some muscle diseases. A muscle biopsy or muscle enzyme test is performed to see the extent of muscle damage.

In order to treat this condition, it is necessary to know the underlying factor causing low creatinine.

Muscle disease: If the underlying cause is a muscle disease, treatment is aimed at reducing muscle pain, weakness and degeneration.

Decrease in muscle mass: If low creatinine levels are observed due to decreased muscle mass, drug treatment may not be necessary. In this case, changes in lifestyle and nutrition are necessary to increase muscle mass. Increasing the difficulty level of the exercises and exercising regularly increases muscle mass. If low muscle mass is caused by malnutrition or excessive weight loss, it is recommended to frequently consume foods containing plenty of protein.

Liver disease: If the underlying cause of low creatinine level is impaired liver function, it is recommended to make changes in nutrition as well as medication. These changes include proper nutrition and limiting or even quitting alcohol consumption if possible.