A urinalysis is used to examine the composition and characteristics of urine. It can also detect abnormal substances in the urine. This allows the doctor to draw conclusions about certain diseases. The urine sample required for the test is usually collected from the so-called midstream urine.
Here you will find further information as well as a selection of doctors who perform urine tests.
Along with a physical examination and a medical history interview, a urinalysis is a fundamental medical diagnostic method. It is used to
- examine the composition and characteristics of urine, as well as
- to detect a wide variety of substances in the urine.
In this way, the doctor can draw conclusions about certain diseases, such as
- diabetes mellitus,
- kidney infections, or
- urinary tract infections such as urethritis or ureteritis
.
A urine test can detect, among other things, substances such as
- blood (red or white blood cells),
- sugar (glucose),
- protein, and nitrite, as well as
- bacteria or other pathogens
in the urine. In addition, a urinalysis can be used to
- the color,
- the odor, and
- the volume of the urine sample
can be examined and assessed.
A urinalysis is also known as a urine test, urinary examination, or urine analysis.
When is a urinalysis performed?
Symptoms and conditions that may require a urinalysis include, among others:
- bladder infections
- Urinary tract infections
- Kidney infections
- Diabetes mellitus
- Kidney dysfunction
- Bladder dysfunction
- Increased urine production
- Unclear abdominal symptoms
- Unexplained flank pain
initial findings during urine tests © Lothar Drechsel | AdobeStock
How is a urinalysis performed?
The urine sample for a urinalysis is usually collected from the midstream urine. This refers to the middle portion of the urine stream, i.e., the urine that is already flowing. The first stream of urine is therefore discarded. Only the subsequent portions of urine are collected in a sterile container and used for the urine test.
This reduces the likelihood that contaminants and bacteria from the external genitalia and the outer sections of the urethra will enter the urine sample. These could skew the results of the urine analysis.
In addition, some urine tests are also performed using what is known as a 24-hour urine collection. For this, the patient must, if possible, collect all the urine they pass within a 24-hour period in a special container.
The urine test itself is performed either
- as a rapid urine test or
- through microscopic examination in the laboratory
.
In a rapid urine test, the examining physician dips a special test strip into the collected urine sample. If the test strip changes color, this indicates the presence of certain substances in the urine.
Microscopic examination of the urine sample in the laboratory is used for further urine analysis. Among other things, this allows for a more precise identification of bacteria or pathogens in the urine. The composition of the urine can also be subjected to chemical analysis.
What values are determined during a urinalysis, and how are they interpreted?
As part of the urinalysis, the following factors and values, among others, are determined and evaluated:
- Volume: The urine test records the daily volume of urine excreted. A healthy person produces an average of 500 to 2,000 millimeters of urine per day. If the measured volume deviates from normal values, this may indicate certain medical conditions.
- Color and odor: As part of the urinalysis, the doctor assesses the color and odor of the urine sample. Normally, urine should be clear and yellow (straw to amber) and not cloudy.
- pH level: The pH level of urine is normally between 5 and 6, meaning urine is slightly acidic. A urine test can detect deviations from this normal range. Acidic urine with a pH level below 5 may indicate, among other things, severe diarrhea or diabetes mellitus. A pH level above 6 may be the result of a urinary tract infection.
- Protein (albumin): A healthy person normally excretes no protein—or only very small amounts—in the urine. If protein is detected in the urine during a urine test, this may indicate kidney disease.
- Sugar (glucose): Once blood glucose levels exceed a certain threshold, the kidneys can no longer reabsorb the sugar. It then enters the urine and is excreted. The presence of sugar in the urine may indicate diabetes mellitus or certain types of cancer.
- Nitrite: Certain urinary tract bacteria lead to the formation of nitrite. Its detection is an indication of a urinary tract infection, such as a bladder infection.
- Ketones: Ketones are not normally present in urine. If they are detected in a urine test, this is a sign of increased fat breakdown in the body. It could also indicate poorly controlled diabetes mellitus.
- Blood (red or white blood cells) in the urine: Red blood cells in the urine can be a sign of inflammation of the urinary tract or bladder cancer. White blood cells in the urine indicate inflammation of the kidney or bladder.
- Bacteria: If bacteria are present in the blood, more detailed laboratory urine tests are usually necessary. There, the exact pathogen is identified.
