Urinalysis (EAS): what it is for, preparation and results

The collection of urine for the exam can be done at home and does not require fasting, but it must be taken to the laboratory within 2 hours for analysis. The type 1 urine test is one of the most requested tests by the doctor, as it informs several aspects of the person's he alth, in addition to being quite simple and painless.

In addition to the EAS, there are other tests that evaluate urine, such as the 24-hour urine test and the urine culture test, in which the pee is analyzed in order to identify the presence of bacteria or fungi.

What the EAS exam is for

The EAS exam is requested by the doctor to evaluate the urinary and renal system, being useful to identify urinary infections and kidney problems, such as kidney stones and kidney failure, for example. Thus, the EAS exam serves to analyze some physical and chemical aspects and the presence of abnormal elements in the urine, such as:

Physical aspects: color, density and appearance;
Chemical aspects: pH, nitrites, glucose, proteins, ketones, bilirubins and urobilinogen;
Abnormal elements: blood, bacteria, fungi, protozoa, sperm, mucus filaments, casts and crystals.

Furthermore, the urinalysis checks the presence and quantity of leukocytes and epithelial cells in the urine.

The collection for performing the urinalysis can be done in the laboratory or at home and the first urine in the morning must be collected, disregarding the first stream. Before performing the collection, it is important to clean the intimate region with soap and water to prevent contamination of the sample. After urine collection, the container must be taken to the laboratory within 2 hours for analysis.

24-hour urine test

The 24-hour urinalysis helps to identify small changes in urine throughout the day and is done by accumulating all the urine eliminated during the day in a large container. Afterwards, this sample is taken to the laboratory and analyzes are carried out to verify its composition and quantity, helping to identify changes such as kidney filtration problems, protein loss and even preeclampsia in pregnancy. Learn more about the 24-hour urinalysis.

Type 1 urine test reference values

The type 1 urine test reference values should be:

pH: 5, 5 and 7, 5;
Density: from 1.005 to 1.030
Characteristics: Absence of glucose, proteins, ketones, bilirubin, urobilinogen, blood and nitrite, some (few) leukocytes and rare epithelial cells.

If the urine test reveals positive nitrite, the presence of blood and numerous leukocytes, for example, it may be indicative of a urinary tract infection, but only the urine culture test confirms the presence or absence of infection. However, the type 1 urinalysis should not be used alone to diagnose a urinary problem. Understand what urine culture is and how it is performed.

Ascorbic acid in urine

Usually, the amount of ascorbic acid in the urine (vitamin C) is also measured in order to verify whether or not there was an interference with the result of hemoglobin, glucose, nitrites, bilirubins and ketones, for example.

The increase in the amount of ascorbic acid in the urine may be due to the use of medication or vitamin C supplements or the excessive consumption of foods rich in vitamin C.

How to prepare for the urinalysis

No special care is usually required before performing a urinalysis, however some doctors may ask you to avoid using vitamin C supplements, anthraquinone laxatives or antibiotics such as Metronidazole, some days before, as the results may change.

It is also important to correctly perform the collection of urine, as the collection of the first stream or the lack of correct hygiene can lead to results that do not reflect the patient's condition. In addition, women are not advised to perform a urinalysis during their menstrual period, as the results may be altered.

Urinalysis to detect pregnancy

There is a urine test that detects pregnancy through the amount of hCG hormone in the urine. This test is reliable, however when the test is done too early or incorrectly, the result can go wrong. The ideal time for this test to be done is 1 day after the day that menstruation should have appeared, and it should be done using the first urine in the morning, since this hormone is more concentrated in the urine.

Even when the test is performed at the right time, the result may be false negative because the body may not yet have produced the hCG hormone in sufficient quantities to be detected. In this case, a new test must be carried out after 1 week. This urine test is specific to detect pregnancy, so other urine tests such as the type 1 urine test or urine culture, for example, do not detect pregnancy.