Kidneys (Urine Tests): Evaluation of laboratory results

 

Kidneys (Urine Tests): Evaluation of laboratory results

Kidney disease very often develops without more serious symptoms or complaints. Therefore, laboratory screening for kidney function is very important in order to detect and treat the disease at the earliest possible stage.

Laboratory testing of urine plays an essential role in diagnosing kidney disease, as a kidney disease is often asymptomatic, and it is the only way to get rid of the often-insidious kidney disease that has been lurking for years. This screening is usually performed by a GP with an annual frequency of two years between the ages of 25 and 40 and over the age of 40.

It is always the responsibility of the GP to evaluate the results of the urine test, together with the laboratory. Deviation alone does not necessarily mean illness; it is always a medical task to make a diagnosis and order further tests.

 

But what exactly is urine and what tests can your doctor ask for?

Urine is a fluid that is filtered and excreted by the kidneys from the blood. The amount of urine that fluctuates between 1000 and 1500 milliliters a day depends on the amount of fluid you take in. Quantities below or above the limits are different from normal.

The color of the urine is straw yellow, which is darker with little fluid intake and lighter with clear fluid intake. Certain medicines and foods (beets, pumpkins, beets) also affect its color.

Urine can be tested with test strips or under laboratory conditions.

 

The following parameters are generally examined during a urine test:

1. Albumin (protein)

In a healthy kidney, only the so-called small proteins may appear in the urine, but so little that the test strip does not show it, only the larger amount of protein. If the rapid urine test is positive, further laboratory testing is recommended.

The presence of the protein in the urine can also indicate a number of diseases, such as inflammatory or immunological diseases of the kidneys and concomitant urinary tract infections.

In diabetes, protein is often excreted in the urine, at which point kidney complications should be considered and further testing is recommended.

The protein also appears frequently in febrile illnesses and in pregnant women, in which case a control test is recommended. Protein depletion during pregnancy may be a sign of pregnancy toxicosis.

Often in young people, protein is excreted in the urine during the day, which disappears when lying down at night, a completely harmless phenomenon.

 2. Sugar (glucose)

The kidneys pass sugar through a certain level of blood sugar and it appears in the urine, in which case further tests are suggested for diabetes. If your blood sugar level is normal, you may also have sugar in your urine if you have kidney disease, which can also be considered a sign of the disease.

Sugar positivity can also be seen with certain medications (steroids, vitamin C) or sudden consumption of large amounts of sugar. In case of expectant mothers, additional blood glucose testing is definitely recommended.

3. Pus (bacteria), nitrite

Nitrite positivity indicates the presence of bacteria and urinary tract infection (inflammation of the urethra, bladder, renal pelvis) or inflammation of the prostate is likely. Bacteria and / or white blood cells can also be detected in the sediment test. Asymptomatic bacterial emptying often occurs as a side effect, such as infection of the urine from the skin or vagina in women. In pregnant women, asymptomatic bacterial shedding should also be taken seriously and treated.

4. Urobilinogen (UBG), bilirubin

Urobilinogen is also found in the urine in physiological cases, the amount is significant. If the level is lower than the reference value, we can think of bile duct obstruction, liver disease, if the level is higher, some hematopoietic disease or certain liver diseases.

Bilirubin does not normally appear in the urine and its positivity is suspected in liver, gallstones and pancreas.

5. Acetone

Acetone in the urine shows a disorder of sugar metabolism. Its levels rise primarily in starvation conditions, such as diabetes or alcoholism. In addition, it may be higher in dehydration (diarrhea or vomiting), after physical exertion or in acute inflammation of the pancreas.

6. Urine sediment

Blood (RBC): May occur in menses, urinary / renal pelvic infections, bladder / kidney tumors, kidney stones.

In many cases, the consumption of a significant amount of beets and beets causes false-positive results.

Marathon runners can have blood in their urine, which is later eliminated, only temporary due to extreme physical activity.

 

White blood cell (fvs): an abnormally high value indicates a lower or upper urinary tract infection, but can even be a sign of an infectious venereal disease.

Epithelial cells: may be derived from the kidneys or urinary tract, they are mostly insignificant.

Cylinders: may indicate kidney disease.

Urine crystals: usually not relevant.

 

7. Urine specific gravity

The specific gravity of urine is greatly influenced by the amount of fluid consumed.

Concentrated urine has a higher specific gravity, urine is dark, denser, and is a sign of dehydration.

Dilute light straw yellow, has a lower specific gravity, and may be a sign of a lot of fluid intake or a disease of the kidneys' ability to concentrate.

8. Urine pH

The chemical effect of urine is not very important in the diagnosis of diseases; The chemical activity (pH) of the urine can vary from 4.5 to 8.5.

9. Selected materials

Urea / Nitrogen: The end product of protein degradation. In the case of decreased kidney function, the amount in the urine decreases, but the value of urea nitrogen in the blood increases.

Creatinine: Creatinine comes from the muscles. Impaired kidney function decreases in the urine but increases in the blood. The two substances (urea nitrogen and creatinine) are tested together to assess kidney function.

10. GFR / (creatinine clearance)

A decrease in GFR indicates the function of kidney function at a very early stage, so it is very important in screening for kidney failure.