There are several ways to identify tuberculosis - Mantoux test, a test for Pirke's reaction, sputum analysis and others. Tuberculosis of the lungs is easiest to diagnose on the basis of fluorography. Unfortunately, most of these tests often give false positive and false negative results, which need additional confirmation. That's why the blood test for tuberculosis is gaining in popularity - this method has a lower probability of error.
How justified is a blood test for pulmonary tuberculosis?
If you are interested in what blood tests can be useful for tuberculosis, it can be confidently said that all compulsory laboratory tests will be useful to some extent. Let the general blood test fail to detect the presence of a Koch bacillus, or other mycobacteria that cause tuberculosis, it helps to track the general health of the patient. Especially well demonstrates the ability of immunity to resist infection. Changes in the analysis of blood in tuberculosis primarily affect the leukocyte formula and sedimentation rate of erythrocytes, ESR. If the indicators appear to the doctor suspicious, he will assign additional studies, such as:
- sputum analysis;
- bronchoscopy ;
- fluorography ;
- tuberculin tests.
The latter analysis can not be considered effective when a person has already been given BCG vaccine. That is why the diagnosis of tuberculosis is being increasingly used to analyze blood, which reveals antibodies to mycobacteria of tuberculosis, MBT. In total, several types of research are used:
- a quinthyferon test for tuberculosis;
- linked immunosorbent assay;
- T-SPOT test;
- polymerase chain reaction.
Benefits of blood tuberculosis diagnosis by blood analysis
The name of each blood test for tuberculosis clearly reflects the essence of the study. The quantified test is based on the detection of an interferon reaction in the blood in the blood, that is, it determines the antibodies. This study is quite accurate, but it can not be used to determine if the bones, lungs, or other organs are affected.
Immunoenzymatic analysis also reveals in the blood antigen antibodies, enzymes produced by the action of immunity. In parallel, the study shows the ratio of different molecules and the qualitative-quantitative component of the blood, which facilitates the establishment of a final diagnosis.
The T-SPOT test is very fast and efficient. The analysis is based on the counting of T cells in the blood. These cells are specifically activated by antigen to MBT. The test allows to reveal both open and closed form of the disease, it is exact by 95%.
Polymerase chain reaction, or PCR, is a hypersensitive experimental technique based on the analysis of certain DNA fragments in the blood. This is a complex study, but its accuracy is the greatest.
Here are the main advantages of detecting tuberculosis from a blood test:
- ability to calculate any form of the disease in a few hours;
- no need to re-analyze;
- low probability of false positive and false negative results;
- high accuracy of the study.