Urinalysis
introduction
The urine test is one of the most common tests in internal medicine and a simple, non-invasive method of obtaining information about pathological processes in the kidneys and the urinary tract such as the bladder or urethra. It may also be possible to draw conclusions about systemic diseases.
The simplest urine test is that Urine test strips, which is held in the midstream urine and by discoloration of test fields the To be available certain substances like Ketones, nitrite, Proteins, Inflammatory cells, sugar, PH value, blood and Bilirubin indicates.
Besides that you can Urine cultures to the Bacteria detection and the so-called Urine sediment create a urine test for solid and cellular components in the urine.
Who needs a urine test?
A urine test is needed to identify pathologies in the urinary tract and kidneys. Patients who Painful urination or in the flank should have a urine test done by the doctor. Infection with bacteria comes into consideration here.
Also at Blood in the urine or foamy urine , a urine test should be done. To the Causes of blood in the urine belong among other things Urinary tract infection and inflammation of various structures of the kidney, such as the calyx or the renal pelvis.
Even if on the body Water deposits (Edema), a urine test is useful to detect proteins that have been lost in the urine. Diabetes mellitus-Patients may show increased sugar levels in the urine test, in addition to getting it Pregnant women heaped a urine test.
How old can the urine be?
The urine test, like any other test, is prone to errors; values and results can be falsified by errors in execution or measurement.
In general: the fresher, the better.
However, the shelf life of the sample depends on the type of urine test. If the doctor wants to create a urine sediment, it is recommended that the urine should not be older than 2 hours before centrifugation. Urine for the test strip examination should be used fresh, maximum within 1-3 hours.
If you stand for a long time, many of the values are falsified, as metabolic processes and degradation processes in the urine continue and make the sample unusable. The urine should also be as fresh as possible for a culture of bacteria.
So if you are invited to a urine test, it is advisable to give the urine fresh in the practice or to collect it shortly before arriving at the doctor, otherwise you may be asked to go to the toilet again.
You may also be interested in this topic: Why is urine yellow?
Do I have to stay sober before the examination?
In addition to the question of the age of the urine, the question arises for many patients: Do you have to be sober to obtain a correct urine sample?
The answer is that you can not sober has to come for a urine test. Normal eating and drinking habits are allowed as these do not directly affect the results of the urine test. The only thing you should pay attention to is before a urine test not too little and not too much to drink. One would like to get a picture of the processes taking place in the body as precisely as possible, but a changed fluid intake can affect the urine too much concentrate or dilutewhich makes the values more difficult to assess.
Normal values of a urine test
For a urine test there are certain values determined by studies, the normal values, which can be pathological if exceeded.
The valid values of a healthy person for a test strip are:
- pH 4.5-8
- Protein <10 mg / dl, whereby the test strip only measures the protein albumin, smaller proteins are not recorded
- Glucose up to 15ml / dl, even healthy people excrete small amounts of glucose in the urine
- Ketones negative
- Bilirubin and urobilinogen negative
- Blood (here is hemoglobin meant) negative
- Erythrocytes <2 / microliter
- White blood cells <25 / microliter
- Nitrite negative
- specific gravity 1.012-1.030 g / ml
These values are standard values and can differ slightly from laboratory to laboratory. For urine testing using urine culture, ideally no bacteria can be detected in the urine. However, almost every sample is slightly contaminated in terms of measurement and removal technology, so that values of bacteria up to 100,000 / ml can still be regarded as normal.
It is important to know that the values of the respective urine test are not sufficient to make a definitive diagnosis, but rather allow us to look in the right direction and, together with further tests and clinical observations, lead to the goal.
Read more on this topic at: urine pH
Urine examination with test strips
The most common and easiest urine test is the test strip. It is a thin test strip a few centimeters long that is briefly dipped into a small urine sample. Ideally, midstream urine is examined, i.e. the first milliliters of urine and the last drops are discarded.
There are up to 11 test fields on the test strip, each of which measures one of the following common ingredients:
- Erythrocytes / blood
- nitrite
- Leukocytes
- Proteins
- Ketone bodies
- Glucose
- Bilirubin
- Urobilinogen
- PH value
- specific weight
A change in color of the field on the test strip, which is compared with color tables, shows the measurement result. This urine test is semiquantitative, which means that, in addition to its presence, it also indicates whether little, medium or a lot of a substance has been detected, usually with the information +, ++ and +++.
Blood components and leukocytes indicate damage to the kidneys or the lower urinary tract.
An indication of bacterial infections is positive nitrite, a degradation product of bacteria, whereby some bacteria do not form nitrite and thus cannot be measured.
Glucose is important in the diagnosis of diabetes mellitus.
Ketone bodies indicate ketoacidosis in the context of poorly controlled diabetes.
If the test strip shows bilirubin or urobilinogen, the liver should be examined more closely.
A positive protein field and increased specific weight speak for a damaged kidney, especially in the form of glomerulonephritis.
The pH value should always be determined and is e.g. also decreased in the context of ketoacidosis.
As a cheap and quick urine test, the test strip can provide many important indications of a clinical picture, but final diagnoses usually require further tests.
Read more at: urine pH
Urine sediment
The urine sediment, or sediment for short, is next to the test strip second most common urine test. The substances dissolved in the urine are not examined, but only solid components. These are through Centrifugation the urine sample obtained and viewed under a microscope.
The sediment can be used to assess the presence of Leukocytes, Erythrocytes and most importantly, misshapen and damaged red blood cells. In addition, certain cell complexes, called cylinders, can be detected as well as various types of crystals. Also Pathogen can be proven directly. The sediment gives clues Kidney damage, Infections mainly of bacterial origin or Systemic diseases, tumors are one of them.
Urinalysis during pregnancy
During pregnancy, the urine test plays an important role as it leads to the Pregnancy check-ups every 4 or every 2 weeks heard.
Due to the close anatomical relationships between the urinary tract and the uterus carrying the child, diseases or inflammations of the urinary tract should be detected early. The urine test that will be done is that Test strips. By recording leukocytes, nitrite and erythrocytes, conclusions can be drawn that the urinary tract is infected, even if there are no symptoms such as pain.
Pregnant women are at increased risk of urinary tract infections, and any urinary tract infection as well as asymptomatic bacteriuria are treated. In addition, the urine test can detect glucose, i.e. sugar, in the urine. During pregnancy, this should be seen as an indication of gestational diabetes, which can develop during pregnancy and which requires special treatment.
Furthermore, the urine examination with test strips records the presence of proteins in the urine that physiologically should not be found there. This Proteinuria can indicate inflammation of the kidneys, but in pregnancy it is of greater interest to recognize one pre-eclampsia. This is the most common pregnancy complication, as Pre-stage of eclampsia and HELLP syndrome can be seen. These are potentially life-threatening clinical pictures during pregnancy for the child and the mother. Early signs is next to one high blood pressure of the Detection of proteins in the urine test, so that the importance of the urine test during pregnancy becomes clear here. In addition, the detection of blood in the urine during pregnancy can indicate a rare systemic Lupus erythematosus be.
Shows the urine test Ketone bodies on, this may be an indication of a wrong diet be in pregnancy with too few carbohydrates. In addition to the test strip, another urine test such as a bacterial culture to determine the pathogen or the sediment test may be necessary.
