VERIFIED CONTENTAuthor: lek. Patryk Jasielski
Urine can undergo changes in many diseases, not only those affecting the kidneys and urinary system. Abnormalities can be seen with the naked eye (discoloration, foaming, cloudiness) or using a microscope and special laboratory techniques. Urinalysis can tell a lot about your he alth and is therefore one of the most basic and routine tests. When should urine alarm you?
Urine, produced by the kidneys, is used by the body to remove unnecessary waste products. It also allows you to remove excess water, electrolytes and other substances. A urinalysis is used to assess whether the urine is normal. They are usually made from a sample of the first or second morning urine. The urine sample is collected in a special, sterile container. It should be tested within 2 hours after collection. The general analysis of urine consists of the assessment of physical, biochemical and morphological characteristics. In addition to a general examination, urine levels of electrolytes, hormones and drugs can be measured in the urine.
What are the characteristics of normal urine?
Normal urine is urine collected from a he althy person and meets the laboratory criteria and is within the reference value range, which is 95% of the general human population. Within a day, 600 to 2500 ml of urine is normally excreted.
It consists of approximately 96% water, 2.5% nitrogen-containing metabolic products (such as urea, creatinine and uric acid), 1.5% mineral s alts (mainly phosphates, chlorides and carbonates) and a minimal amount of other substances, incl. dyes.
Normal urine is clear, light yellow (straw-colored). It has a pH (i.e. acid-base) of about 5-6 (i.e. slightly acidic) and has a characteristic, slightly intense smell.
Its density, i.e. specific gravity depending on the content of dissolved particles, is about 1.023 g / ml. About 150 mg of protein are lost in the urine per day. However, standard analysis methods are not sensitive enough, so normal urine does not contain protein.
Similarly, glucose should not be detected in it. They are also looking for urobilinogen and bilirubin, which are components of bile acids produced bythe liver. The correct concentration of urobilinogen is 1 mg / dl (deciliter).
In the urine of he althy people, single blood cells are also found. The presence of up to 3 red blood cells (red blood cells) in the microscope's field of view and up to 3 leukocytes (white blood cells) is considered normal.
He althy urine is sterile (no bacteria) and no blood rolls (damaged cells or insoluble proteins present in the urine sediment) are found, except for vitreous rolls.
Check what the color of urine means
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Changes in urine physical characteristics
The physical features of urine include:
- color,
- fragrance,
- specific gravity,
- foaming,
- cloudiness
- and pH.
A disturbing symptom that you can observe on your own is red urine. There are several reasons for this condition. This may indicate the presence of blood, hemoglobin, urobilinogen and bilirubin.
Some drugs can change the color of urine. The urine also turns red after eating beetroot or pine nuts. Milky white color and turbidity accompany urinary tract infections. Clouding is most often the result of the precipitation of urinary stones, made of crystals of phosphate or urate.
The change in smell may be diet-related - for example, asparagus gives the urine its characteristic odor. Other causes of odor changes include urinary tract infections, cancer, and metabolic disorders.
The specific gravity, or the density of urine, can be lowered or increased. In the case of disturbed concentration, urine has a specific gravity below 1.023 g / ml. This is the case with hyperthyroidism and adrenal function, hypothyroidism, electrolyte disturbances and kidney damage.
Concentrated urine, i.e. more than 1.035 g / ml, occurs when glucose, ethyl alcohol and other substances are present in it.
Another abnormal feature is foaming of urine. This can be a disturbing symptom that there is too much protein in the urine (i.e. proteinuria), amino acids or bile s alts (if the bile duct is blocked). If such a symptom is observed, it is recommended to perform a urine test.
The final physical property of urine is its pH. When it is lowered, it indicates acidification of the organism, e.g. in the case of kidney damage, ingestion of toxins or urinary tract infection. It may be the result of electrolyte disturbances (hyperkalemia, i.e. excess potassium in the body) or hormonal disorders (hyperthyroidism).
Increased pH may also be infectious, result from disorderselectrolytes (hypokalemia, i.e. low amounts of potassium) or hormones (e.g. in adrenal insufficiency).
Changes in biochemical characteristics of urine
The biochemical features of urine include the presence of protein, bile pigments, glucose, ketone bodies, nitrites and leukocyte esterase.
There are many reasons for the presence of protein in the urine, i.e. proteinuria. It can be due to the presence of myoglobin and hemoglobin (these are blood pigments) from broken red blood cells. It is often the first symptom of chronic renal failure and is associated with the majority of diseases of this organ of various degrees.
It also occurs in urinary tract infections. Proteinuria is not always disease. It may appear slightly after physical exertion, with prolonged standing, it may be an admixture of menstrual blood.
Only urobilinogen and bilirubin are determined from the bile pigments. Their elevated levels in the urine are the result of liver diseases (mainly inflammation) and biliary tract diseases (gallbladder and bile duct stones).
Glucose in urine occurs when it is high in blood. It is often found in untreated type I diabetes and type II diabetes. Ketone bodies are also often found in diabetes. They also occur in people who are starved for a long time and who perform intense physical exercise.
Determination of leukocyte esterase and nitrite of bacterial origin is used to diagnose the presence of bacteria in the urinary tract. The determination of nitrite is an easy, screening test that is performed with strips.
Changes in urine morphological features
The morphological features of urine are the presence of bacteria, erythrocytes, leukocytes and rolls. Normal urine should not contain bacteria. They can be a sign of a urinary tract infection. However, keep in mind that bacteria often get into the urine sample by accident during urine collection.
Urine should be collected from the middle stream. After washing the urethra and passing a portion of urine to the toilet, the next portion should be collected in the test container. In the absence of urinary symptoms, the presence of the bacteria themselves should not be of concern. We are talking then about asymptomatic bacteriuria. In most cases it does not require any treatment.
The presence of erythrocytes is found in the case of urinary tract infection during menstruation. They can appear after a lot of physical exertion. They often accompany diseases and injuries of the kidneys or urinary tract. It may be the first symptom of kidney or bladder cancer. Please note that it always requires further diagnosis. Leukocytes in the urine are found primarily in the case ofurinary tract infections.
Rolls are found in urine sediment. They are solids from centrifuged urine. They are made of various proteins and cells embedded in them. Depending on what they are made of, we distinguish granular rollers made of cell elements. They testify to damage to the kidney parenchyma. Others are leukocyte rolls, found in kidney infections. Erythrocytic, typical for glomerulonephritis and epithelial in damage to the renal tubules.
The urine test is a simple and accessible test. However, it can tell a lot about the state of the body's functioning. It allows you to diagnose not only kidney diseases, but also other organs. If you notice with the naked eye any abnormalities in the form of a red color of the urine or cloudiness, it is worth going to the doctor.
Similarly, when it foams or has a disturbingly changed smell. You should also check your urine regularly, even if you don't see anything disturbing in it. This may allow for early detection of the disease and implementation of appropriate treatment.