Creatinine is a chemical by-product generated during the normal muscle metabolism process as tissues breakdown. Once produced, it gets filtered by the kidneys before being excreted out of the body through urine. Creatinine level in the blood is an indicator of kidney health and functioning. The ability of kidneys to clear creatinine out from the blood and make it creatinine-free is known as creatinine clearance rate (CCR). CCR, in turn, depends on the rate of blood flowing through the kidneys i.e. the glomerular filtration rate (GFR).
The kidney creatinine levels are directly dependent on a person’s muscles. This means that if a person has more muscles, then they’ll be producing more creatinine. The creatinine levels in the blood are indicators of how much muscles a person has and their kidney functioning. Some other factors determining the quantity of creatinine in kidneys are body size, amount of activity, and medications.
Generally, the kidney creatinine levels found in men are around 0.6 to 1.2 milligrams/deciliters (mg/dL). The same in women are found to be around 0.5 to 1.1 mg/dL. Women are found to have lesser kidney creatinine as compared to men since they have lesser muscles.
Why is Creatinine Clearance so Important?
Since direct measurement of GFR is difficult, doctors take creatinine clearance as an indicator of GFR and, subsequently, kidney function. Normal creatinine clearance level is 125ml/min in a healthy adult. Low creatinine clearance means the impaired ability of kidneys to filter blood and hence impaired renal function.
Measuring Creatinine in Blood
Creatinine level in blood serves as an indicator of GFR or renal function. Blood creatinine level is inversely proportional to GFR i.e. higher the level of creatinine in blood, lower the GFR, and more impaired the kidney function. Higher blood creatinine level also means lower creatinine clearance. The test to measure the creatinine level in blood is known as serum creatinine test.
Understanding Kidney Creatinine Levels
Many people are unsure about when to worry about kidney creatinine levels or what level of creatinine indicates kidney failure. Generally, high creatinine levels aren’t something to worry about in isolation, however, they can be an indicator of adverse health risks, including chronic kidney diseases.
This is where serum creatinine comes in as it can help detect problems in the functioning of kidneys. As mentioned above, your estimated glomerular filtration rate (eGFR) can help in determining whether your kidneys are successfully clearing the blood. The serum clearance test is important in calculating your eGFR. In case you suffer from chronic kidney diseases, eGFR can help figure out which stage of chronic kidney disease you are in.
Creatinine levels in urine are also a good way to determine the functioning of your kidneys. Generally, the accepted creatinine levels in urine are from 955 to 2,936 milligrams (mg) per 24 hours for men, and 601 to 1,689 mg per 24 hours for women. If your creatinine levels are out of this range, it can indicate that you may have
- Kidney disease
- Kidney infection
- Urinary tract obstruction, for example, kidney stones
- Muscular dystrophy
- Myasthenia gravis
The tests can reveal whether you have high or low creatinine. Some of the high creatinine causes are:
- Chronic kidney diseases
- Kidney obstruction
- Excess consumption of protein
- Rigorous exercise
Low creatinine levels are caused as a result of:
- Low muscle mass
- Excessive weight loss
Elevated Blood Creatinine Level – Symptoms
Renal dysfunction may present in a variety of ways and in some cases, there may be no symptoms at all. However, common high creatinine symptoms are extreme unexplained fatigue and/or lethargy, dehydration, reduced urine output and/or darkened colour of urine, swelling over feet, face, under the eyes, etc.
Probable Causes and/or Symptoms of High Creatinine in Blood
Kidney Pain: It manifests as pain in the upper back region, under the ribs and common symptoms of kidney pain include painful urination, mild to moderate fever, nausea, vomiting, etc.
Kidney Failure: The diagnosis of kidney failure depends heavily on Creatinine test results. In the early stages, kidney failure presents itself as extreme fatigue, shortness of breath, heart arrhythmia, high blood pressure, etc.
Kidney Infection (Pyelonephritis): It’s usually caused by bacteria entering the urinary tract through the anus or vagina. Infection impairs the ability of the kidneys to filter blood and, in turn, the high blood creatinine levels. Chances of kidney infection are high during pregnancy, unprotected sexual intercourse, diabetes, kidney stones, urinary tract surgery, or use of catheters or in people having a past history of chronic urinary tract infections. Symptoms of the infection are often the same as those experienced in kidney pain. Though kidney infection is fully curable with antibiotics, early detection and treatment are important to prevent its spread to the bloodstream and other parts of the urinary tract.
Hypertension related kidney disease: Hypertension impairs blood vessels thereby hampering the ability of kidneys to filter blood and remove waste from the body. When hypertension is the underlying cause, symptoms of kidney disease often include elevated blood pressure, swelling caused by fluid retention in lower extremities, frequent night time urge for urination with decreased urine output. In such cases, controlling high blood pressure with medication and diet is the most recommended line of treatment.
Diabetes: Diabetes is a major risk factor for kidney disease as it injures small blood vessels thereby impairing kidney function and putting kidneys at risk of infection from excessive waste build-up.
Prostate Problems: Prostate is a male gland located below the urinary bladder. Studies have revealed that men who face prostate issues such as prostate enlargement, cancer, etc., are three times more likely to develop kidney disease than those who don’t.
Bile Duct Cancer or Cholangiocarcinoma: Bile duct filters bile, a by-product of liver metabolism. In cases of bile duct cancer, the build-up of excessive bile impairs renal function by hampering their ability to filter blood.
Leprosy: Leprosy patients often experience nephritis i.e. inflammation of nephrons or kidney cells thereby leading to impaired renal function.
Poly-cystic kidney disease: It presents usually in adults as numerous cysts growing in the kidneys. Symptoms include persistent or intermittent pain in the lower back, on the sides, and in between ribs and headaches.
Hemolytic Uremic Syndrome (HUS): This condition is marked by the destruction of red blood cells, low platelet count, and renal failure. Symptoms often include bloody vomiting, diarrhoea, purpurae formation or bruising, lethargy, etc.
Kidney Dysplasia: This is characterized by abnormal kidney development (one or both) in babies while they are in the womb. Such babies often require treatment such as dialysis and kidney transplant early in life.
How to Check Kidney Function at Home
The latest innovations in medical science have made it possible for you to carry out a kidney test at home. New innovation uses a smartphone-enabled home urinalysis device for detecting problems in kidney functioning, especially chronic kidney diseases. The urine test can help in the detection of albumin. Moreover, the urinalysis test can be done at home and the results can be reviewed by doctors. It’s extremely important for chronic kidney diseases to be diagnosed early since they may lead to renal and cardiovascular diseases. This new innovation may increase the testing power of many people, thereby increasing the detection of kidney diseases, reducing their propensity, and preserving kidney functioning.