Urine culture for microflora is a diagnostic method that is prescribed to detect urinary tract infection. Among the main indications: suspicion of inflammation, complaints of fever and dysuria, as well as control of therapy.
Urination is, at first glance, a simple process: urine is formed in the kidneys, enters the bladder, from which it is excreted through the urethra. Each person perceives this process as ordinary, and, often, no one pays attention to it until some problems appear.
OAM and Nechiporenko urinalysis
Complete urinalysis (CAM) is a laboratory test that evaluates the chemical and physical characteristics of urine and sediment. Physical characteristics are relative density (specific gravity), reaction, transparency, color, amount of urine. Chemical characteristics - bile pigments, ketone bodies, glucose, protein. Sediment microscopy allows detecting casts, epithelial cells, leukocytes, erythrocytes, salts.
OAM is one of the most common tests, as it allows you to determine the function of the kidneys and urinary system.
Urinalysis (AM) according to Nechiporenko allows you to determine the number of cylinders, erythrocytes and leukocytes in one milliliter of urine. The procedure is simple and efficient. The method allows you to determine the presence of an inflammatory process in the kidneys or in the urinary system. Usually, a healthy person has an approximate number: leukocytes up to 4000 (in women) and up to 2000 (in men), erythrocytes up to 1000, and cylinders up to 20.
Urine culture for microflora is a laboratory test that allows you to determine the presence of a variety of pathogenic microorganisms in the urine. The main task of the analysis is to prove the etiological role of microorganisms in the development of various diseases of the genitourinary system. In the urine of a healthy person there are no microorganisms, in other words, it is completely sterile.
If their presence was determined during the study period, this is a direct indicator of the presence of infection in the urinary system. Urine culture for flora is usually prescribed after deviations in the results of OAM and AM according to Nechiporenko have been found.
Among the indications for obtaining a referral for a urine culture for microflora, it is worth noting:
- monitoring the effectiveness of treatment;
- changes in urinalysis;
- urinary disorders;
- pain and cramps during urination;
- antibiotic susceptibility testing.
Preparation for diagnostics
Diagnostic results directly depend on the correctness of the study. The doctor necessarily explains to the patient that this study will help determine the presence of a urinary tract infection. Before the analysis, you do not need to introduce any dietary restrictions. The patient is told in detail how to properly collect urine (a bias is made to the toilet of the external genital tract immediately before the analysis is taken). If necessary, urine is taken with a special catheter. If there is a suspicion of tuberculosis, urine is taken in the morning for three consecutive days. It is important to tell your doctor if you are taking antimicrobials. The patient must purchase a sterile urine collection jar and gloves from the pharmacy.
Urine sampling algorithm for analysis
Urine sampling for analysis is carried out in special sterile containers: after thorough hygiene of the genital organs in a volume of five to ten milliliters of morning average urine. If a permanent type catheter is installed, it must be pinched, wiped with an alcohol ball, and using a needle, urine is aspirated in a volume of ten milliliters. The jar is carefully and tightly closed and immediately sent for analysis to the laboratory.
There is a special sticker on the jar, which indicates the patient's name, preliminary diagnosis and other necessary additional information.
In the laboratory, urine samples are placed in various culture media and cultured under appropriate conditions. Each type of bacteria for a certain period of time forms colonies, which then determine the type of bacteria and the result of the analysis.
Improper sampling technique may affect results. A false-negative answer can be obtained: in case of violation of the terms of sending the collected urine for analysis; when the patient is taking antimicrobial drugs (these parameters must be indicated on the jar without fail).
Interpretation of the results obtained
The results of the analysis are for diagnostic purposes. The unit of measurement is the number of colony-forming units (CFU) per ml, deciphered as follows:
- The degree of bacteriuria, not exceeding 103 microbial cells in 1 ml of urine, indicates the absence of an inflammatory process and usually the result of urine contamination.
- The degree of bacteriuria, equal to 104 microbial cells in 1 ml of urine, is regarded as a questionable result. The study should be repeated.
- The degree of bacteriuria equal to or greater than 105 microbial cells in 1 ml of urine indicates the presence of an inflammatory process.
A quantitative result is important not only for determining the degree of contamination, but also for monitoring the correctness of the treatment, and also allows you to differentiate the infectious process in the urinary tract from urine contamination with normal microflora.
Keep in mind that the results will not come until seven days later. An analysis collected on time and in accordance with all the rules allows you to correctly diagnose and choose an effective treatment.
- Laboratory and instrumental studies in diagnostics: Handbook / Per. from English. V. Yu. Khalatov; under. ed. V. N. Titov. - M.: GEOTAR-MED, 2004. - 960 p.