What is creatinine and how it should be normal

What is creatinine

Creatinine is a chemical compound that formed in muscles after they produce energy. When muscles use energy, the tissue that makes up them breaks down and creatinine enters the bloodstream and is then filtered by the kidneys and excreted in the urine. Therefore, the level of this substance is an indicator of the work of the excretory organs.

What can be learned from the level of creatinine

Using a serum creatinine test Can find out how damaged the excretory organs are, determine whether the treatment has helped or whether the transplanted kidney is working normally. True, usually for this you need to calculate the glomerular filtration rate, but more on that below.

Also, creatinine with other indicators is included in blood chemistry, which is needed to determine the state of the main organs and systems.

How much creatinine should be normal

Reference values depend from age:

Also, the amount of creatinine depends on race, sex and body size. Therefore, checking only the level of a substance in the blood is not the best way. estimate the state of the excretory system. The result will not be very objective.

Why creatinine may be below normal

reasons decrease Not much creatinine

• starvation;
• consumption a large number fluids (water dilutes the blood, so the percentage of creatinine decreases, although the absolute level does not change);
• amyotrophy.

Why creatinine may be higher than normal

Creatine rises due to problems with the kidneys, cardiovascular and endocrine system, muscles, lifestyle habits and medications taken. These are situations like:

• acute and chronic renal failure (amyloidosis, kidney damage in diabetes mellitus and other diseases);
• insufficiency of the cardiovascular system (myocardial infarction, cardiogenic shock, myocardial dystrophy, and so on);
• massive destruction of muscle tissue, for example, when heavy plates or iron parts fall on the limbs during accidents (crash syndrome), and the release of creatinine from cells;
• burns (due to the simultaneous death of many cells, their contents enter the intercellular substance);
• acromegaly and gigantism - conditions due to an excess of growth hormone;
• hypothyroidism - poor functioning of the thyroid gland;
• dehydration (due to blood clotting, the percentage of creatinine increases, although the absolute level does not change);
• excessive physical activity;
• a diet with a lot of meat: when cooked, creatinine is released, which affects test results;
• radiation sickness, when radiation damages the skin and muscles or kidneys;
• blockage in the urinary tract, due to which urine does not flow freely, but gets stuck and puts pressure on the kidneys;
• taking drugs that are toxic to the kidneys (mercury compounds, sulfonamides, thiazides, antibiotics from the group aminoglycosides, cephalosporins and tetracyclines, barbiturates, salicylates, androgens, cimetidine, trimethoprim-sulfamethoxazole);
• damage to the vessels of the glomerular apparatus of the kidneys (glomerulonephritis), which may be the result of an infectious or autoimmune disease;
• bacterial infection of the kidneys (pyelonephritis);
• death of tubular epithelial cells (acute tubular necrosis) caused, for example, by drugs or toxins;
• decreased blood flow to the kidneys due to shock, dehydration, acute heart failure, atherosclerosis, or complications of diabetes.

When is a creatinine test ordered?

Usually a creatinine test appoint:

• with already known kidney disease: you need to take an analysis once in a while to see if the condition is improving or worsening;
• with suspicion of muscle disease;
• before the hemodialysis - blood cleansing on an artificial kidney machine;
• with dehydration due to illness;
• in preparation for computed tomography;
• before prescribing medicines that can damage the kidneys;
• if you suspect kidney problems.

Kidney problems can be suspected by signs such as:

• weakness;
• fatigue;
• decreased attention;
• poor appetite;
• sleep problems;
• swelling on the face, wrists, ankles;
• ascites (fluid in the abdominal cavity);
• red or coffee-colored urine;
• decrease in the volume of urine;
• burning sensation when urinating;
• jet discontinuity;
• changes frequency of urination;
• the predominance of nocturnal diuresis;
• pain in the lumbar region (especially on the sides of the spine), under the ribs;
• high pressure.

What to do if creatinine is high or low

Usually a doctor prescribes a creatinine test, so any results should be referred to him. If suddenly you yourself decide to take a biochemical blood test, and the level of creatinine is elevated, then you need to make an appointment with a therapist. He will ask about complaints, conduct an examination and help you understand if a narrow specialist is needed.

What other tests with creatinine can be prescribed

In addition to blood creatinine levels, estimate and other indicators.

Glomerular filtration rate

The glomerular filtration rate (GFR) measures how the kidneys filter the blood. Since normal creatinine levels vary greatly from person to person, it is not possible to assess kidney function by this alone. Therefore, a complex formula is used that takes into account gender, race, height and weight. You don’t need to calculate anything yourself - the data is entered into the calculator program, and it already gives the result.

Creatinine clearance

Creatinine clearance measures how the kidneys filter creatinine from the blood to be excreted in the urine. To do this, you need to measure the levels in the blood and urine in the same period of time.

Albumin/creatinine ratio

Albumin is a blood protein. Normally, the kidneys do not filter it, so there is very little or no of it in the urine. The ratio of this indicator to creatinine also demonstrates how the kidneys work.