Tuberculosis is a fairly common infectious disease that can be found literally in any country in the world. The disease can occur due to the ingestion of various bacteria or Koch's bacillus. The disease is most often transmitted by airborne droplets and has severe symptoms, namely:
- dizziness;
- wet cough;
- hemoptysis;
- weakness;
- fever;
- causeless weight loss;
- night sweats.
Tuberculin tests are contraindicated in the presence of various skin diseases, allergic reactions, bronchial asthma, epilepsy, infectious diseases. Samples should not be taken and within one month after the injection of an immunoglobulin or biological sample.
Diagnosis of tuberculosis
The main organ that is damaged by tuberculosis is the lungs. Other internal organs rarely suffer from such a disease. It is possible to diagnose tuberculosis with the help of fluorography, CT (computed tomography), radiography, skin tuberculin test (Pirke test) and other types of laboratory tests. In order to diagnose the disease, vaccination is carried out once a year.
What is a skin test reaction?
One of the methods of preventive testing of children for tuberculosis is the test of Pirke. This immunological test is able to show whether there is a tuberculosis infection in the growing body, even in the early stages. The reaction of the body to the appearance of tuberculin is called the Pirke reaction, and it determines the sensitivity of the body to mycobacteria of tuberculosis. The Pirke test is also done to patients of an already adult age group as a control analysis in assessing the effectiveness of treatment.
Sample Composition
The sample contains tuberculin - a special extract from the destroyed Koch bacilli, invented back in 1890 by the German doctor Robert Koch. It was this doctor who became the pioneer of a disease such as tuberculosis. The hood began to be used in 1907. Initially, it lubricated the skin and monitored the reaction, and after tuberculin began to try to enter subcutaneously.
Today, Pirke test, the composition of which includes a mixture of dead filtrates of the culture of human and bovine microbacteria, is observed in many people of different age groups. In addition to the active main substance - tuberculin Pirke, the sample includes such additional substances:
- salts of phosphate buffered saline ;
- sodium chloride.
How does this happen?
The principle of action of the sample, the composition of which is based on tuberculin, consists in the cutaneous application of the drug. The skin of the forearm or shoulder is well disinfected only with carbolic acid, because alcohol-containing substances leave protein on the skin, which is undesirable for conducting a clean analysis. Notches on the skin are made using a scarifier with a depth of not more than 5 mm. The patient needs to wait up to 5 minutes until the solution is absorbed, and the residues are carefully wiped with a paper towel. After the procedure, the patient is monitored for 48 hours and the reaction to the substance is analyzed.
As a result of the introduction of tuberculin at the site of scratches, a specific inflammation (papule) occurs, which is provoked by the accumulation of T-lymphocytes. It is these blood cells that are responsible for anti-tuberculosis immunity. The skin can change color and density in the papule. This method of diagnosis is rarely used due to its low information content and low diagnostic efficiency. After the test has been made and before obtaining the results it is not recommended:
- wet the place where the test was made;
- wipe the papule with various medicines or ointments;
- stick a papule with a band-aid;
- comb or tear.
results
On average, when the Pirke test is performed, the results are evaluated after 2-3 days, that is, 48-72 hours. At the place where the scratches were made, a focus of irritation appears. Its area is measured by doctors. The results are classified in this way when the Pirke test is performed:
- the norm is observed with a minimum measure of papule measurement (on average up to 5 mm);
- an indicator of 3 mm indicates the need for re-vaccination and re-analysis of the result of irritation;
- if a papule with sizes from 4 to 10 mm is detected, this means a possible infection with tuberculosis or a person at risk (that is, constant contact with an infected person);
- if the focus of irritation has a size of 10 to 15 mm or ulcers are found at the vaccination site, then this indicator indicates a high probability of contracting tuberculosis.
Graduated sample
This type of study is improved and is a cutaneous application of the drug with a few scratches. Unlike the traditional research option, a graduated test allows you to determine the differential diagnostic value in the process of determining the nature of the allergy to tuberculin. A skin test is carried out by applying tuberculin to the skin with a 100%, 25%, 5% and 1% concentration. Preparation of the skin is carried out in the same way as in the traditional test Pirke. The notches are applied strictly in order, and various marked pipettes are used. Only sterile materials are used for each patient. After the appearance of the “white roller”, tuberculin residues can be removed. This type of diagnosis is most often carried out in order to determine the effectiveness of the treatment of tuberculosis.
Graduated Test Results
A graded skin test of Grinchar and Karpilovsky is evaluated after 48-72 hours after the procedure. There are such reactions of the body to various concentrations of tuberculin:
- anergic reaction (no reaction to samples);
- nonspecific reaction (you can notice only slight redness on the sample with a 100% concentration of the solution) ;
- a normergic reaction (a moderate response of the body to tuberculin is observed, and there are no reactions to samples with a 5% and 1% solution);
- hyperergic reaction (this result is characterized by a response to all types of samples; the higher the concentration of tuberculin in the solution, the greater the reaction);
- leveling type of reaction (all samples taken have the same papules, skin colors and sizes of foci of inflammation);
- paradoxical reaction (with a higher concentration of tuberculin in the sample, a more pronounced reaction is observed).
So, we examined such a diagnostic method as the Pirke test. Its result does not indicate the localization of the disease in the body or the person’s ability to infect healthy people. It only indicates the reaction of the body to the causative agent of tuberculosis. The Pirke test (Mantoux reaction - its alternative) is considered mandatory for childhood.