A sputum culture is the primary test used to diagnose tuberculosis.
Your doctor asks you to cough deeply to produce mucus from the lower airways, which is called sputum.
After you spit the mucus into a container, specialists examine the sample for bacteria..
Mycobacterial culture is the gold standard for the diagnosis of M. tuberculosis because of its lowest limit of detection (LOD \x26lt; 10 organisms).
However, it can be impaired by situation that affect mycobacterial growth such as the introduction of an antibiotic treatment before sampling (van Zyl-Smit et al., 2011).Mar 2, 2023.
The Mantoux tuberculin skin test (TST) or the TB blood test can be used to test for M. tuberculosis infection..
Mycobacterium colonies, generally the causal agent in tuberculosis, usually grow within 28 days and are easily recognized by their "cauliflower" aspect.
The niacin test is used for formal identification.
Currently, radiometric respirometry allows detection of M..
The presence of bacteria is accomplished by examination of stained smears made from a portion of the clinical sample, culture techniques, molecular/immunological methods, or a combination of these methods..
The accurate diagnosis of TB can be performed in a reliable way at the lab showing the presence of bacilli in a specimen of the lesion by means of smear microscopy, culture or a rapid molecular test (like the Xpert MTB/Ultra RIF or the TB-LAMP)..
People diagnosed with TB using culture, rapid molecular tests recommended by WHO, lateral flow urine lipoarabinomannan (LF-LAM) assays or sputum smear microscopy are defined as “bacteriologically confirmed” cases of TB..
Skin test.
A tiny amount of a substance called tuberculin is injected just below the skin on the inside of one forearm.
Within 48 to 72 hours, a health care worker will check your arm for swelling at the injection site.
The size of the raised skin is used to determine a positive or negative test..
Bronchoalveolar lavage samples the distal portions of the lungs and provides abundant material for study (washings and brushing and biopsy specimens), which can help obtain a rapid diagnosis of tuberculosis.
Pooled respiratory tract specimens are unacceptable due to extensive bacterial overgrowth and contamination..
The confirmation of TB disease still rests upon identification or isolation of M. tuberculosis bacilli from a clinical sample.
This can be achieved by smear microscopy for acid-fast bacilli (AFB), mycobacterial culture or nucleic acid amplification (NAAT) tests..
On March 24, 1882, Dr.
Robert Koch announced the discovery of Mycobacterium tuberculosis, the bacteria that causes tuberculosis (TB)..
Test for TB Infection
The Mantoux tuberculin skin test is performed by injecting a small amount of fluid called tuberculin into the skin in the lower part of the arm.
The test is read within 48 to 72 hours by a trained health care worker, who looks for a reaction (induration) on the arm..
WHO criteria employs simple clinical features and chest X-ray (Table 1).
These include prolonged duration of cough and/or fever, failure to thrive or severe malnutrition, result of TST, suggestive physical findings, and a positive chest X-ray (Table 1)..
Mycobacterium tuberculosis is often difficult to find.
This is because of its thick cell wall and its ability to live in isolated body cavities without air, which cannot be reached (see A description of the TB germ).
For this reason, the health worker often needs to combine the investigations described above..
These abnormalities may suggest TB, but cannot be used to definitively diagnose TB
However, a chest radiograph may be used to rule out the possibility of pulmonary TB in a person who has had a positive reaction to a TST or TB blood test and no symptoms of disease
5 Diagnostic MicrobiologyIn the absence of a positive culture, TB disease may also be diagnosed on the basis of clinical signs and symptoms alone
A negative culture means that M tuberculosis was NOT identified in the specimenHowever, this does not exclude diagnosis of TB disease
A sample of blood is sent to a lab
One lab test finds out whether certain immune system cells can "recognize" tuberculosis
A positive test shows that you have either a latent TB infection or active TB disease
Other tests of the blood sample can help determine if you have active disease
The microbiological detection of TB is critical because it allows people to be correctly diagnosed and started on the most effective treatment regimen as early as possible
People diagnosed with TB in the absence of bacteriological confirmation are classified as “clinically diagnosed” cases of TB
Indian Government institute
Radiology used in the diagnosis of tuberculosis
Indian Government institute
Radiology used in the diagnosis of tuberculosis
