Pirke test: readings, evaluation of results

Tuberculosis is a fairly common infectious disease that can be found literally in any country in the world. The disease can occur because of the ingress of various bacteria or Koch's rods into the body. The disease is most often transmitted by airborne droplets and has a severe symptomatology, namely:

• dizziness;
• Wet cough;
• Hemoptysis;
• weakness;
• Feverish condition;
• Causeless weight loss;
• Night sweats.

Tuberculin tests are contraindicated in the presence of various skin diseases, allergic reactions, bronchial asthma, epilepsy, infectious diseases. Do not make a sample and within one month after the injection of an immunoglobulin or a biological sample.

Diagnosis of tuberculosis

The basis of the organ that is damaged in tuberculosis is the lungs. Other internal organs rarely suffer with 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. To diagnose the disease, the vaccination is carried out once a year.

What is the reaction of the cutaneous test?

One of the methods of preventive study of babies on tuberculosis is the Pirke test. This immunological test is able to show whether there is a tuberculous infection in the growing organism, even in the early stages. The reaction of the body to the appearance of tuberculin is called the reaction to Pirke, and it determines the sensitivity of the organism to the mycobacteria of tuberculosis. Pirke sample is also made to patients already adult age group as a control analysis in assessing the effectiveness of treatment.

Sample composition

The composition of the sample includes tuberculin - this is 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 such a disease as tuberculosis. Extraction began in 1907. Initially, it lubricated the skin and followed the reaction, and after tuberculin began to try to inject subcutaneously.

To date, Pirka's sample, which includes a mixture of killed filtrate cultures of microbacteria of human and bovine types, is observed in many people of different age groups. In addition to the active principle substance - tuberculin, Pirke's sample includes such additional substances:

• Salt phosphate buffer solution ;
• sodium chloride.

How does this happen?

The principle of action of the sample, whose composition is based on tuberculin, is the dermal application of the drug. Skin covers of the forearm or shoulder are well disinfected only with carbolic acid, because alcohol-containing substances leave the skin on the skin, which is undesirable for carrying out the purity of the analysis. The incisions on the skin are made with the help of a scarifier not more than 5 mm deep. The patient should wait for up to 5 minutes until the solution is absorbed, and the residues are gently wiped with a paper towel. After the procedure, the patient is observed 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 (papula) occurs, which is caused by the accumulation of T-lymphocytes. It is these blood cells that are responsible for antituberculous immunity. Skin covers can change the color and density in the area of the papule. This method of diagnosis is used quite rarely because of its low information content and low diagnostic efficiency. After the sample was made and before the results are not recommended:

• Wet the place where the sample was made;
• Wipe the papule with various medicines or ointments;
• To seal the papule with plaster;
• 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. On the place where the scratches were made, a foci of irritation appears. His 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 indication of 3 mm indicates the need for re-vaccination and re-analysis of the result of irritation;
• If a papule with a size of 4 to 10 mm is detected, this means a possible infection with tuberculosis or the presence of a person in the risk group (that is, a constant stay in contact with the infected person);
• If the focus of irritation is 10 to 15 mm in size or ulcers are found at the vaccination site, then this indicator indicates a high probability of infection with tuberculosis.

Graduated test

This type of research is improved and is a skin application of the drug with a few scratches. Unlike the traditional version of the study, a graduated test allows you to determine the differential diagnostic value in the process of finding out the nature of the allergy to tuberculin. The skin test is carried out by applying to the skin of tuberculin with 100%, 25%, 5% and 1% concentration. Skin preparation is carried out in the same way as in the traditional Pirke test. The incisions 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" you can remove the remains of tuberculin. This type of diagnosis is most often performed in order to determine the effectiveness of treatment of tuberculosis.

The results of the graduated test

Graduated skin test of Grinchar and Karpilovsky is evaluated after 48-72 hours after the procedure. There are such reactions of the body to different concentrations of tuberculin:

• Anergic reaction (no reaction to the tests);
• Nonspecific reaction (you can see only a slight redness on the sample with a 100% concentration of the solution) ;
• Normal reaction (moderate response to tuberculin is observed, and reactions to samples with 5% and 1% solution are completely absent);
• Hyperergic reaction (this result is characterized by a response to all types of samples, the higher the concentration of tuberculin in solution, the greater the reaction);
• Equalizing type of reaction (all samples made have the same papules, skin color and the size of the foci of inflammation);
• A paradoxical reaction (at a higher concentration of tuberculin in the sample, a more pronounced reaction is observed).

So, we have considered such a method of diagnosis as the Pirke test. Its result does not speak of the localization of the disease in the body or of the person's ability to infect healthy people. It shows only the reaction of the organism to the causative agent of tuberculosis. The Pirke test (Mantou's reaction is its alternative) is considered compulsory for holding in childhood.