Creatinine is a natural waste product formed in the body with daily muscle activities. It is filtered by the kidneys and excreted via urine. Creatinine level is an indicator of muscle mass in the body and kidney function. High levels in the blood or urine indicates a dysfunction in the kidneys. Low level of creatinine shows a decrease in the muscle mass as the body gets older or it may be caused by a temporary situation such as a pregnancy or malnutrition. Diet and physical activity play a role in regulating creatinine levels.
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Creatinine is a waste product in the body. It is formed from the breakdown of a compound called creatine produced by muscles. It is also known as serum (blood) creatinine; its level in blood changes depending on age, gender, and muscle mass. It is one of substances that kidneys filter and eliminate.
This process helps keep the normal level of creatinine in the body. When the kidneys do not work properly, it is accumulated in the blood and the level elevates. Creatinine test provides important information about the general state of health.
Although it is a waste product, it can play a role in fighting diseases by preventing bacterial growth in the body.
An elevation in the level of creatinine in the blood shows excessive creatine production in the body. There are many conditions that can lead to elevation in creatinine level:
High creatinine levels indicate that creatinine is not filtered, not properly excreted from the body, and there is a problem in the kidneys. While high levels in infants are associated with bacteremia, it may be an indicator of prostate cancer in adult males. (2)
The best way to reduce the level is to treat the underlying cause. Many diets and lifestyle changes may also be helpful. Reducing red meat intake or avoiding high-intensity exercises may support the treatment.
If it is caused by acute or chronic renal damage, the level will not decrease until the problem is solved. If it temporarily elevates due to dehydration, high protein nutrition, the use of supplements, reversing the conditions will reduce the level.
If creatinine level is higher than normal range, the results are confirmed by another blood or urine test. If renal damage is concerned, conditions that can cause the damage are examined. Change in diet and lifestyle help lower the level, but the treatment of the underlying condition is the only way to keep creatinine level stable in the long term.
Many athletes and bodybuilders take creatine supplements to make their muscles more stable. Muscles use creatine for energy. If not used, it is converted into creatinine. Creatinine level may increase due to muscle damage resulting from high-intensity exercise in athletes. It is an expected and normal situation. (3,4)
Creatinine can be tested via the blood and urine. Serum creatinine is the test for the amount in the bloodstream, while creatinine clearance is the test of the level in urine. (5)
It is a blood test to measure the amount of creatinine in the bloodstream. Serum creatinine helps identify the glomerular filtration rate (GFR), an indicator of general kidney function. GFR is a calculation including creatinine, age, gender, and weight. (6)
Serum creatinine level in females is lower than males as they have less muscle mass. Normal ranges may differ among laboratories. Generally it ranges from 0.6 to 1.2 mg/dL in males and 0.5 to 1.1 mg/dL in females.
It shows the amount of creatinine cleared out of the body or how well kidneys filter the waste. It requires a combination of urine test and blood test. As urine has to be collected over a period of 24 hours, it is usually done after evaluating serum creatinine test and calculating the GFR. (7)
The frequency of the test depends on the underlying conditions and the risk of renal damage. Regular testing is recommended in the following situations:
Creatinine level is expressed in milligrams per decilitre (mg/dL) or micromol per litre. The normal range of creatinine in the blood may be 0.84 to 1.21 milligrams per decilitre (74.3-107 micromoles per litre). A GFR of ≥60 is considered normal and a rate of < 60 may indicate a kidney disease. A level of 15 or less is defined as kidney failure.
Low creatinine levels may indicate that the liver or muscles are not working properly.
In general, low level of creatinine shows insufficient production of it in the body. It may be an indicator of a problem regarding the muscles, liver, or may be the result of a temporary condition such as pregnancy and malnutrition.
It may indicate an underlying health problem, such as liver disease. However, it is usually part of aging or a temporary condition that can be treated with changes in diet.
Symptoms do not clearly indicate low creatinine levels in most cases. Symptoms vary depending on the underlying condition.
If test results confirm low levels, additional tests are recommended to eliminate muscle diseases. A muscle biopsy or muscle enzyme test is performed to check for muscle damage. Treatment options depend on the underlying cause.
The body regularly produces a fixed amount of creatinine. The kidneys, on the other hand, are responsible for keeping the level in the blood within the normal range. Therefore, creatinine is a reliable indicator of kidney function. Each kidney has millions of small blood filtering units called nephrons. Nephrons constantly filter the blood through a very small set of blood vessels known as glomeruli. Toxins are stored in the bladder and excreted through urine.
An increase in creatinine level in the blood indicates that kidney function is impaired. It is one of many factors to consider when deciding on dialysis treatment when kidney function is very low. As kidney disease does not show symptoms in the early stages, people at high risk should be tested regularly. (9)
It is important to know how long the procedure leading to kidney dysfunction takes and whether the dysfunction is recent or not. It is easy to treat with early diagnosis. A serious infection can damage the kidneys or weaken the person’s bloodstream without a treatment.
Creatine is a part of the cycle that produces the energy needed for muscles to contract. It is an amino acid that helps supply energy to cells in the body, especially to muscle cells. The produced amount depends on the age and muscle mass of the body. It is found naturally in red meat and fish. It can also be obtained from supplements.
Creatine supplements are very popular among athletes who try to increase strength and muscle volume, especially among bodybuilders. It is the most effective nutritional supplement that can be used to adapt to high-intensity training.
When creatine is broken down for energy, creatinine is formed as a chemical waste. As almost all of creatinine is filtered by the kidneys and excreted from the body in urine, their blood levels are an indicator of kidney function.
Keratin is a fibrous protein. It is included in structures such as horn, nail, hair, skin, tooth, and it increases their endurance. Keratin filaments are very robust in structure.