Creatinine in the blood is low - causes in women, men, children; norms; treatment

What causes a decrease in creatinine levels, and what can be done to keep their levels within normal range?

When the body uses the amino acid creatine for energy, creatinine remains as waste. Creatinine levels in the blood or urine can be checked if there is concern about liver or muscle disease.

Most often, low creatinine levels are a sign of age-related muscle loss, or it is a temporary condition during pregnancy, illness, or malnutrition. Low creatinine levels in older people or people with low body weight should not be a serious cause for concern.

How to make an appointment with a pediatrician

Examination of children, collection of anamnesis and prescription of tests is performed by the pediatrician of JSC "Medicine" (clinic of academician Roitberg). You can figure out why your child’s creatinine is low or high, and you can examine the current state of health at an appointment by making an appointment by phone: +7 (495) 995-00-33. The clinic is located at the address: Moscow, 2nd Tverskoy-Yamskaya lane, building 10. This is the center of Moscow, so there are many metro stations nearby: Mayakovskaya, Chekhovskaya, Tverskaya, Belorusskaya, Novoslobodskaya. If you wish, you can make an appointment on the website of JSC “Medicine” by filling out the “Make an appointment with a doctor” form. You must provide your contact phone number and name. After this, a call will be received from the clinic to coordinate the date and time of the appointment.

What is creatinine?

Creatine

is an amino acid produced naturally in the body and obtained in small quantities from food. Creatine has gained popularity as a dietary supplement following evidence that it can increase body weight, improve physical endurance and speed recovery. When creatine is broken down, it is used for energy and creatinine remains as waste products. Creatinine levels vary depending on factors such as height, age, or gender, so there is no standard value.

Normal creatinine

All creatinine cannot be filtered and excreted by the kidneys. This is due to the fact that it is constantly released into the blood while the muscle tissue is viable. Blood plasma should contain a relatively stable concentration of creatinine, which may vary depending on age, muscle activity and nutrition. Therefore, there are maximum and minimum limits of normal creatinine, which take into account all these points and indicate the normal functioning of organs.

To eliminate errors in the results of a biochemical blood test based on creatinine levels, be sure to adhere to the general rules for blood sampling. The study must be carried out in the morning on an empty stomach. It is advisable to avoid strong muscle strain and overheating or hypothermia before directly drawing blood.

To illustrate the variations in creatinine standards, they are presented in table form:

Creatinine norm in women

Plasma creatinine concentrations in women should be lower than in men. This is due to the physiological mechanisms of its formation, distribution and circulation in the blood.

The mechanisms of this phenomenon are as follows:

• A woman's muscle mass is less than that of a man;
• Less muscle strain;
• The activity of metabolic processes in the female body is reduced;
• Food products from the female diet contain less exogenous creatinine entering the body;
• The influence of sex hormones and pregnancy.

Creatinine norm in men

The creatinine of the male body should almost always be higher than that of women of the same age group. This is due to lifestyle characteristics and differences in the functioning of organs and systems. Age characteristics also affect the process of creatinine metabolism, both towards its increase and decrease. Recently, many men have been visiting gyms and using doping products containing creatine to increase muscle performance. This must be taken into account when assessing the creatinine norm.

Normal creatinine level in children

The concentration of creatinine in a child’s plasma largely depends on his age. The main fluctuations in this indicator are associated with growth activity and the degree of increase in muscle mass over a certain period of time. Newborns, due to the high stress that their body had to experience during childbirth, have creatinine levels the same as in adults. The same feature is typical for adolescents, which is explained by the active growth of the body. School-age children grow relatively steadily, so their creatinine levels are slightly lower than adults.

What does a low creatinine level mean?

Low creatinine levels may indicate a problem with the muscles or liver, but can be caused by something less serious, such as loss of muscle mass in older people, or pregnancy.

Creatinine is always present in the bloodstream, from where it is removed by the kidneys and excreted from the body in urine. Research shows that creatinine helps fight disease and stops the growth of bacteria. A laboratory test used by doctors shows how well the kidneys remove creatinine from the body.

There are four main causes of low creatinine:

1. low muscle mass;
2. liver diseases;
3. diet;
4. pregnancy.

Low muscle mass

Creatinine levels are often related to muscle mass, which can decrease with age or illness. A low level may indicate that muscle mass is reduced, such as in muscular dystrophy. Older people often lose muscle mass as they age, and this is not usually a serious medical problem.

Liver problems

Creatine is produced by the liver, and an unhealthy liver will not be able to produce normal amounts of creatine. Chronic liver disease can cause a 50% reduction in creatine production. This means there will be a low level of creatinine in the blood, which can be checked by a blood test.

Diet

Although creatine is produced naturally, small amounts come from food, so diet may influence low creatinine levels. Creatine is primarily found in meat, so people who follow a vegetarian or low-protein diet tend to have low creatinine levels.

Pregnancy

Pregnancy often causes low creatinine levels, which will return to normal after childbirth.

Serum creatinine (with GFR determination)

Creatinine is a product of the non-enzymatic breakdown of creatine and creatine phosphate, which is formed in muscles. It is excreted from the body by the kidneys.

Synonyms Russian

1-methylglycocyamidine, a product of the conversion of creatine phosphate, creatinine in the blood.

English synonyms

Creatinine, Creat, Serum Creat, Cre, Blood creatinine, Serum creatinine, Urine creatinine.

Research method

Kinetic method (Jaffe method).

Units

μmol/L (micromoles per liter).

What biomaterial can be used for research?

Venous, capillary blood.

How to properly prepare for research?

• Do not eat for 12 hours before the test.
• Avoid physical and emotional stress 30 minutes before the test.
• Do not smoke for 30 minutes before the test.

General information about the study

Creatinine is a residual product produced in muscles when a substance called creatine is broken down. Creatine is part of a cycle that provides the body with energy to contract muscles. After 7 seconds of intense physical activity, creatine phosphate is converted to creatine, which then turns into creatinine, which is filtered in the kidneys and excreted in the urine. Creatine and creatinine are stably produced by our body in constant quantities. Almost all creatinine is excreted by the kidneys, so its concentration in the blood is a good indicator of kidney function. The amount of creatinine produced depends on total body weight and, in particular, muscle mass. Therefore, for example, creatinine levels in men will be significantly higher than in women and children.

A small part of it (15%) is secreted by the tubules, but it is mainly produced due to filtration in the glomeruli. The level of creatinine in the blood does not go beyond the normal range until glomerular filtration rate decreases to critical values, especially in patients with low muscle mass. The creatinine level then rises.

It is precisely because of the large number of components (muscle mass, gender, age) that affect the concentration of creatinine in the blood that this study is not the best screening test for detecting renal failure. At the same time, creatinine is a more sensitive indicator of kidney disease than urea.

What is the research used for?

• To assess renal function.
• To assess the function of major organs and systems (in combination with other studies).
• To evaluate kidney dysfunction and the effectiveness of its treatment if creatinine or urea are outside the normal range and the patient has an underlying chronic disease, such as diabetes, that affects the kidneys.
• If the level of creatinine in the blood and urine is known, the creatinine clearance (Rehberg test) can be calculated - this test shows how effectively the kidneys filter small molecules such as creatinine from the blood.
• To calculate the glomerular filtration rate to confirm kidney damage.

When is the study scheduled?

• At certain intervals in case of already known kidney disease or a disease that can cause deterioration of kidney function (together with a test for urea and microalbuminuria).
• When diagnosing skeletal muscle diseases.
• Before and after the hemodialysis procedure.
• For symptoms of kidney dysfunction: weakness, fatigue, decreased attention, poor appetite, sleep problems,
• swelling of the face, wrists, ankles, ascites,
• foamy, red or coffee-colored urine
• decreased diuresis,
• problems with urination: burning, intermittency, change in frequency (predominance of nocturnal diuresis),
• pain in the lumbar region (especially on the sides of the spine), under the ribs,
• high pressure.

What do the results mean?

Reference values ​​(creatinine norm):

Creatinine

GFR (glomerular filtration rate): 60 and above.

Causes of increased creatinine levels

• Acute and chronic renal failure (amyloidosis, kidney damage due to diabetes, etc.).
• Failure of the cardiovascular system (myocardial infarction, cardiogenic shock, myocardial dystrophy, etc.).
• Massive destruction of muscle tissue (crash syndrome) and release of creatinine from cells.
• Burns (massive necrosis of cells with the release of their contents into the intercellular substance).
• Acromegaly.
• Gigantism.
• Hyperthyroidism.
• Dehydration (blood thickening and relative hypercreatininemia).
• Excessive physical activity.
• Excessive consumption of meat products.
• Radiation sickness.
• Obstruction of the urinary tract.
• Taking nephrotoxic drugs (mercury compounds, sulfonamides, thiazides, aminoglycoside antibiotics, cephalosporins and tetracycline, barbiturates, salicylates, androgens, cimetidine, trimethoprim-sulfamethoxazole).
• Damage to the blood vessels of the glomerular apparatus of the kidneys (glomerulonephritis), which may be a consequence of an infectious or autoimmune disease.
• Bacterial kidney infection (pyelonephritis).
• Necrosis of the tubular epithelium (acute tubular necrosis), caused, for example, by drugs or toxins.
• Prostate disease, nephrolithiasis or other factors causing obstruction of the urinary system.
• Reduced blood flow to the kidneys due to shock, dehydration, acute heart failure, atherosclerosis, or complications of diabetes.

Reasons for decreased creatinine levels

• Starvation.
• Overhydration (blood dilution – relative hypocreatininemia).
• Amyotrophy.

What can influence the result?

• Factors distorting the result Pregnancy (especially the first and second trimesters).

Important Notes

• The creatinine content is reduced in pregnant women by almost half due to an increase in blood volume (hypervolemia), increased blood flow in the kidneys and, accordingly, an increasing degree of filtration; all this leads to an increase in creatinine clearance (excretion in urine).
• In older people, creatinine formation normally decreases; this must be taken into account when determining the severity of their kidney disease.
• Some people who have had chronic kidney failure for several years have normal creatinine levels.

Also recommended

• General urine analysis with microscopy
• Rehberg test (endogenous creatinine clearance)
• Serum uric acid
• Uric acid in daily urine
• Albumin in urine (microalbuminuria)
• Urea in serum
• Urea in urine
• Creatinine in daily urine
• Potassium, sodium, chlorine in daily urine
• Serum potassium
• Serum sodium
• Chlorine in serum
• Phosphorus in daily urine
• Serum phosphorus
• Serum calcium
• Calcium in daily urine
• Ionized calcium

Who orders the study?

Therapist, urologist, nephrologist, infectious disease specialist, endocrinologist, gynecologist, cardiologist.

Symptoms of low creatinine levels

Symptoms of low creatinine depend on the underlying condition, but may include:

• With low muscle mass
  - weakness, difficulty performing physical exercises;
• With liver disease
  - weakness, pain in the upper right corner of the abdomen, nausea;
• When dieting
  - weakness or dizziness, weight loss.

In most cases, symptoms do not indicate low creatinine levels, but may indicate other health problems.

Treatment

Low creatinine levels can indicate a variety of medical conditions, so your doctor will use the test results to determine underlying problems. If low creatinine levels, along with other symptoms, indicate liver disease, treatment most likely begins with medications and lifestyle changes. These changes may include eating healthier and avoiding alcohol.

If a person has a muscle disorder, treatment may include exercise therapy, medications, or surgery.

When is the analysis performed?

The referral is issued by a general practitioner, nephrologist, infectious disease specialist, gynecologist or endocrinologist. Indications for analysis:

• signs of disease of the urinary system: change in the color of urine, difficulty urinating, pain or cramping, persistently high blood pressure, pain in the lumbar region, swelling, insomnia, weakness and poor appetite;
• the need for hemodialysis and evaluation of its effectiveness;
• control over the effectiveness of treatment methods for kidney pathologies;
• identification of complications when taking nephrotoxic drugs;
• advanced diagnostics of skeletal muscle diseases;
• severe dehydration of the body;
• preparatory procedures before computed tomography.

Venous blood is collected for the study.

How to increase creatinine levels?

Exercising to increase muscle mass and increasing creatine intake in the diet can help people, especially those on a vegetarian diet.

For people who perform high-intensity exercise, creatine as a dietary supplement is considered safe.

Low creatinine levels may indicate underlying health problems such as liver disease. Most often, low creatinine levels are a normal part of aging or a temporary problem that can be resolved by changes in diet.

Ways to normalize creatinine in the blood

As a rule, we are talking here about the physiological reasons for the decrease, therefore, processes that are generally natural for the body should be corrected. The main measures to increase creatinine are:

• ensuring a balanced diet - introducing proteins into the menu in sufficient quantities;
• normalization of the drinking regime - up to 2 liters per day;
• increasing physical activity in order to develop muscles and activate metabolic processes in them;
• taking vitamin complexes and/or sports supplements (for example, protein isolates).

Naturally, before implementing these measures, it is necessary to obtain confirmation of the absence of pathology (mainly liver disease).