Creatinine in Urine

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Creatinine is a decomposition product of creatine, which is an important part of body muscles. Creatinine is withdrawn from the body completely by the kidneys.
Creatinine is created at a steady rate and is affected very little by diet or normal physical activities. When kidneys are damaged and cannot function normally, the quantity of creatinine in the urine decreases while the amount of creatinine in the blood increases.

The creatinine test can be used as a screen to examine kidney function. It can be used as part of the creatinine clearance test as well. It is often used to provide information on other chemical elements in the urine such as albumin or protein.
The test can be done routinely as part of a comprehensive or basic metabolic panel. It can be performed when physician suspects that you are suffering from kidney dysfunction or if you are acutely or chronically ill with a condition that may affect your kidneys and be worsened by kidney dysfunction. Also the test implemented at intervals to monitor treatment for kidney disorder or kidney function while on some medications.
This test examines the amount of creatinine in patient's blood and/or urine. Creatinine is a waste product produced in your muscles from the decomposition of a compound called creatine. Creatine is a product of the cycle that generates energy needed to contract your muscles. Both creatine and creatinine are created by the body at a comparatively constant rate. Almost all creatinine is excreted by the kidneys, so blood levels are a good measure of how well your kidneys are working. The amount produced depends on the size of the person and their muscle mass. In this case, creatinine concentration will be a little bit higher in men than in women and children.

The creatinine blood test is performed along with a BUN (blood urea nitrogen) test to evaluate kidney function. These two tests are frequently ordered as part of a basic or comprehensive metabolic panel (BMP or CMP), groups of lab tests that are used to examine the function of the body's main organs. BMP or CMP tests are used to screen healthy people during routine exams and to help evaluate acutely or chronically ill patients in the emergency room and hospital. If the creatinine and BUN tests are defined abnormal or if patient has a corresponding disorder, like diabetes, that is known to damage the kidneys, in this case, these two tests may be performed to monitor the progress of kidney dysfunction and the efficacy of treatment. Blood creatinine and BUN tests may also be performed to screen kidney function before to some procedures, such as a CT (computed tomography) scan, that may require the use of medications that may affect the kidneys.

A creatinine clearance may be calculated by a combination of blood and urine creatinine levels. This test defines how efficaciously kidneys filter small molecules like creatinine out of blood.
Urine creatinine can be also performed with a variety of other urine tests as a correction factor. Because it is created and excreted at a relatively constant rate, the quantuty of urine creatinine can be compared to the amount of another substance being measured. Examples of this are when creatinine is measured with protein to calculate a urine protein/creatinine ratio (UP/CR) and when it is measured with microalbumin to calculate microalbumin/creatinine ratio (also known as albumin/creatinine ratio ACR). These tests are used to evaluate kidney function as well as to detect other urinary tract disorder.
Serum creatinine examination also are used to calculate the estimated glomerular filtration rate (eGFR), which is used as a screen test to look for signs of kidney damage.

Creatinine test can be performed routinely during a health examination. It may be ordered when patient does not have specific health complaints. It may be ordered when patient is acutely ill, and when doctor suspects the kidneys are not working properly. Some evidences and symptoms of kidney dysfunctions as following:
·Swelling or puffiness, particularly around the eyes or in the face, wrists, abdomen, thighs or ankles  
·Mid-back pain (flank), below the ribs, near where the kidneys are located  
·Urine that is foamy, bloody, or coffee-colored  
·A decrease in the amount of urine  
·Fatigue, lack of concentration, poor appetite, or trouble sleeping  
·Problems urinating, such as a burning feeling or abnormal discharge during urination, or a change in the frequency of urination, especially at night  
·High blood pressure  
The creatinine blood test may be ordered, along with BUN test and microalbumin, at systematic intervals while patient has a known kidney disorder or has a disease that can affect kidney function. Both BUN and creatinine may be performed if a CT scan is planned, before and during specific drug therapies, and prior to and after dialysis to monitor the effectiveness of treatments.

Test results
High creatinine levels in the blood suggest disorders or health problems that affect kidney function. These can include:
·Damage to or swelling of blood vessels in the kidneys (glomerulonephritis) caused by infection or autoimmune disorders  
·Bacterial infection of the kidneys (pyelonephritis)  
·Death of cells in the kidneys' small tubes (acute tubular necrosis) caused, for example, by drugs or toxins  
·Prostate disorder, kidney stone, or other causes of urinary tract obstruction  
·Reduced blood flow to the kidney due to shock, dehydration, congestive heart failure, atherosclerosis, or complications of diabetes  
Blood levels of creatinine may also be elevated temporarily as a result of muscle injury and are generally slightly lower during pregnancy.
Low blood levels of creatinine are not common, but they are also not usually a cause for concern. They can be shown with conditions that result in reduced muscle mass. Low level of blood creatinine indicates nothing more than an efficient and effective kidneys' function.
A further test of renal system is to collect all the urine passed over 24 hours and then to compare the quantity of creatinine in the blood to the level in the blood stream - creatinine clearance test.
This can look at the efficiency of the kidneys and is only usually done if there is an indication of a problem with kidney function.
In good kidneys the creatinine level in the urine compared to the blood has to be high as it is being passed out efficiently.
Vice versa, if the level in the urine is decreased, with a high blood creatinine level, this in an indication of a disease for which a doctor is usually involved.

Levels of 24-hour urine creatinine are evaluated with blood levels as part of a creatinine clearance test.
Random urine creatinine levels have no standard reference ranges. They are usually used with other tests to reference levels of other substances measured in the urine. Some examples include the microalbumin test and urine protein test.
The result of your blood creatinine test is measured by your doctor against a reference range for the test to determine whether the result is "normal" (it is within the range of numbers), high (it is above the high end of the range), or low (it is below the low end of the range). Because there can be many variables that affect the determination of the reference range, the reference range for this test is specific to the lab where your test sample is analyzed. For this reason, the lab is required to report your results with an accompanying reference range. Typically, your doctor will have sufficient familiarity with the lab and your medical history to interpret the results appropriately

Also you should know
Drugs such as aminoglycosides (vancomycin, gentamicin) can cause kidney damage and so creatinine is monitored. Other drugs, such as cephalosprins (cefoxitin), may increase creatinine concentration without reflecting kidney damage.

Moderate exercise will not affect your creatinine levels. As you continue to exercise and build muscle mass, your creatinine levels may increase slightly but not to abnormal levels.

Creatinine levels will not vary with a normal diet. Creatinine levels may be 10%-30% higher in people who eat a diet that is very high in meat.

Creatine is a compound that is made primarily in the liver and then transported to your muscles, where it is used as an energy source for muscle activity. Once in the muscle, some of the creatine is converted to creatinine. The amount of both creatine and creatinine depend on muscle mass, so men usually have higher levels than women. Creatine is now available as a dietary supplement. If you take creatine, your creatinine levels may be higher than when you do not take the supplement. You should tell your doctor about all of the dietary supplements you are taking to help her evaluate your lab results.

Creatinine levels relate to both muscle mass and to kidney function. As you age, your muscle mass decreases but your kidneys tend to function less effectively. The net result is not much change in creatinine levels in the blood as you get older.

Occasionally, a doctor will look at the ratio between a person's BUN and blood creatinine to help them determine what is causing these concentrations to be higher than normal. The ratio of BUN to creatinine is usually between 10:1 and 20:1. An increased ratio may be due to a condition that causes a decrease in the flow of blood to the kidneys, such as congestive heart failure or dehydration. It may also be seen with increased protein, from gastrointestinal bleeding, or increased protein in the diet. The ratio may be decreased with liver disorder (due to decrease in the formation of urea) and malnutrition.

All information on this page is intended for your general knowledge only and does not provide medical advice, diagnosis or treatment.