Creatinine
and Eva Rudolf-Müller, doctorEva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.
More about the experts All content is checked by medical journalists.Creatinine is a metabolic product of creatine from the muscles. Creatine, in turn, is important for muscle contractions. In medicine, creatinine is primarily used as a laboratory parameter for kidney function. Here you can read everything you need to know about the laboratory value, when the doctor will determine it and what increased or decreased creatinine values mean!
What is Creatinine?
Creatinine is a breakdown product of creatine, an important substance for muscle contraction. It was discovered by the German chemist Justus Liebig in the 19th century. While creatine plays a role in muscle work, its metabolic product creatinine - as far as is known - has no significant function.
Creatinine Clearance
As a laboratory value, creatinine must be differentiated from the so-called creatinine clearance. This is a measure of the amount of creatinine excreted by the kidneys.
You can read more about this in the article Creatinine Clearance.
Creatine in the metabolism
Creatine is made in the body in both the liver and kidneys and then transported to the heart and skeletal muscles. In addition, humans take in creatine by eating cooked meat. In the muscles it is both bound to phosphate and in free form. Of the total creatine in the muscle, one to two percent is excreted daily as creatinine via the kidneys with the urine. Very small amounts are also excreted via the intestines and bile.
When do you determine creatinine?
Creatinine is an important parameter for kidney function. That is why the doctor determines the creatinine level if a kidney dysfunction is suspected or checked. This can result from acute or chronic kidney disease, for example. Damage to kidney cells from toxins or from the breakdown of red blood cells or muscle cells can also impair kidney function. Other reasons for the creatinine determination are:
- Metabolic diseases (e.g. diabetes mellitus)
- Collagenoses (connective tissue diseases)
- High blood pressure (hypertension)
- acute loss of volume (due to bleeding or water loss)
The doctor determines the creatinine in the blood (serum or plasma) using an enzyme-based measurement method. It can also measure the creatinine level in the urine (24-hour urine collection).
Creatinine normal value
The following normal values apply to the blood:
|
Normal creatinine value in mg / dl (serum or plasma) |
Creatinine standard value in µmol / l (serum or plasma) | |
|
Men <50 years Men> 50 years |
0,84 - 1,25
0,81 - 1,44 |
74,26 - 132,6 68,0 - 123,8 |
|
women |
0,66 - 1,09 |
53,04 - 96,36 |
|
Children (16-18 years) Children (13-15 years) Children (10 to 12 years) Children (7 to 9 years) |
0,8 - 1,4 0,6 - 1,2 0,6 - 1,0 0,6 - 0,9 |
70,72 - 123,76 53,04 - 106,08 53,04 - 88,4 53,04 - 79,56 |
|
Children (4 to 6 years) |
0,5 - 0,8 |
44,2 - 70,72 |
|
Children (1 to 3 years) |
0,4 - 0,7 |
35,36 - 61,88 |
|
Children (1 to 12 months) |
0,4 - 0,7 |
35,36 - 61,88 |
|
Children (1 to 30 days) |
0,5 - 1,2 |
44,2 - 106,10 |
In addition to kidney function, muscle mass also determines how much creatinine someone excretes. Therefore, body builders and other athletes may consider other blood creatinine levels to be normal.
Creatinine levels in the urine
|
women |
men
| |
|
morning urine test |
260-2170 mg / l |
390-2590 mg / l |
|
24-hour urine collection |
1.0 - 1.3 g / day |
1.5-2.5 g / day |
When is the creatinine too low?
The lower limit for the blood creatinine value is 0.84 mg / dl in men and 0.66 mg / dl in women. If the creatinine is lower, however, this has no medical significance. Such reduced serum values can be found, for example, as secondary findings in the case of underweight, stunted muscles (atrophy) or during pregnancy.
Decreased creatinine levels in the urine occur in degenerative muscle diseases, which are characterized by an increased breakdown of muscle cells. These include, for example, muscular dystrophies and amyotrophic lateral sclerosis (ALS.
When is the creatinine too high?
If the serum creatinine is increased, this can be caused by acute kidney failure as well as chronic kidney disease as well as by lack of water (desiccosis). For example, the following lead to acute kidney failure:
- allergic reactions to drugs or contrast media
- Poisons and heavy metals
- Breakdown of red blood cells (hemolysis) or breakdown of muscle cells (myolysis)
- Plasmacytoma (multiple myeloma)
- Vascular obstruction in the kidney due to a blood clot (thromboembolism of the kidney vessels)
Chronic renal insufficiency, on the other hand, is caused, among other things, by:
- Diabetes mellitus (diabetic nephropathy)
- Glomerulonephritis (inflammatory diseases of the kidney glomeruli)
- Connective tissue diseases (collagenoses)
- high blood pressure
- Cystic kidney disease
However, the creatinine in the blood only rises when kidney function is reduced by at least 50 percent. As a result, kidney diseases in the early stages in the laboratory are not detected by creatinine alone.
Long-term use of certain medications can also cause blood creatinine to rise. These include acetylsalicylic acid (ASA), certain antibiotics (cephalosporins) and pain relievers and anti-inflammatory drugs such as naproxen.
A high creatinine level in the urine can, for example, be caused by high blood pressure due to narrowing of the kidney vessels (renovascular hypertension). The hormone disorder acromegaly also causes the urine level of creatinine to rise.
What to do with altered creatinine
A high creatinine value does not say anything about the cause of the change. In view of the fact that the limit value is exceeded, kidney dysfunction is likely, but not absolutely certain. Depending on the patient's complaints, further examinations must be carried out for more detailed clarification. For example, if the creatinine level is high, the doctor can order an ultrasound examination of the kidneys or a tissue sample to be taken from the kidneys.
Tags: healthy feet medicinal herbal home remedies symptoms
