AFB culture is a laboratory test used to diagnose infections caused by acid-fast bacilli (AFB) bacteria, such as Mycobacterium tuberculosis, which causes tuberculosis (TB). During the test, a sample of bodily fluid, such as sputum or blood, is taken and placed onto a culture medium that provides the nutrients needed for AFB to grow. The culture is then incubated for several weeks to allow the bacteria to multiply. After growth is visible, further tests are performed to identify the specific species of AFB present and determine the appropriate treatment. This test is important for the diagnosis and treatment of AFB infections, including TB and other diseases.
|Related Articles||AFB and Smear Culture|
|Test Purpose||AFB culture is done to find out if you have tuberculosis (TB) or another mycobacterial infection.|
|Test Preparations||Overnight Fasting Is Mandatory For Gastric Lavage Specimens.|
|Test Components||AFB Culture|
|Specimen||1. Blood/Bone Marrow: Collect 8 ML|
2. CSF: Collect 2 ML (1 ML Min.)
3. Pus/Body Fluids (Pleural/Pericardial/Ascitic/ Synovial/Ocular) Aspirates /Semen/ BAL Bronchial Washings: Submit As Much As Possible (1 ML Min.)
4. Endometrial Curettings/Tissue: Submit In Sterile Normal Saline In A Sterile Screw Capped Container.
5. Swabs: Submit Swabs In 1 ML Sterile Normal Saline In Sterile Screw Capped Container.
6. Sputum/Urine: Submit 2 Spot (Random) Morning Samples, 5-10 ML (1 ML Min.) Sputum/10 ML (5 ML Min.) Urine In Sterile Screw Capped Container.
7. Gastric Lavage: Submit 5-10 ML (2 ML Min.) Gastric Lavage In A Sterile Screw Capped Container.
|Stability Room||2 Hrs|
|Stability Refrigerated||48 Hrs|
|Method||Automated Fluorescent, ICT|
|Download Report||Download Report|
Introduction of AFB culture:
Tuberculosis (TB) is a bacterial infection that primarily affects the lungs and is a significant global health concern. However, different cultures may have varying beliefs, practices, and attitudes towards the disease. Culture can impact TB stigma, traditional beliefs and practices, and TB prevention and transmission. Understanding how culture influences TB can lead to more effective prevention and treatment strategies. This topic explores the intersection of culture and TB, highlighting the importance of cultural sensitivity in addressing TB in different communities.
Purpose of AFB Culture:
Here’s a list of the purposes of studying TB culture:
- To understand how cultural beliefs and practices impact TB prevention, treatment, and outcomes
- To develop culturally sensitive TB prevention and treatment strategies
- To address TB stigma and its impact on affected individuals and communities
- To promote understanding and acceptance of TB in different cultural contexts
- To improve communication and engagement with diverse communities affected by TB
- To balance traditional practices and modern medical interventions in TB prevention and treatment
- To reduce the transmission of TB in culturally diverse populations
- To promote equity and reduce disparities in TB prevention and treatment outcomes
- To address cultural barriers to accessing TB prevention and treatment services
- To advance global efforts to control and eliminate TB.
Types of Specimins and Collection for AFB Culture:
here’s some information on the types of specimens and collection methods for TB culture:
Types of specimens:
- Sputum: Sputum is the most commonly collected specimen for TB culture. It is the mucus that is coughed up from the lungs and air passages.
- Bronchoalveolar lavage (BAL): BAL is a procedure that involves flushing the lungs with a saline solution and then collecting the fluid for culture.
- Pleural fluid: This is a specimen collected from the fluid that accumulates around the lungs (pleural effusion). It is collected by inserting a needle through the chest wall and into the pleural space.
- Blood: This is a less common specimen for TB culture, but it can be used to detect the presence of TB bacteria in the bloodstream.
- Cerebrospinal fluid (CSF): used to diagnose TB meningitis
- Tracheal aspirate: This involves suctioning secretions from the trachea for culture.
- Gastric aspirate: This involves collecting stomach contents for culture in young children who are unable to produce sputum.
- Biopsy: A tissue biopsy from an infected area can also be collected for culture.
- Bronchial washings: Bronchial washings are collected by passing a sterile saline solution through a bronchoscope, a flexible tube with a light and camera, and suctioning it back out. This technique is used for patients who cannot produce sputum or have abnormal chest X-rays.
- Urine: Urine samples can be used for TB culture, especially in young children who may have difficulty producing sputum. Urine is collected in a sterile container and tested using a specialized culture method called the urine lipoarabinomannan (LAM) test.
- Spot sputum collection: This involves collecting a single sputum sample from the patient.
- Early morning sputum collection: The first sputum produced in the morning is usually the most concentrated and is preferred for culture.
- Induced sputum collection: This involves using a nebulizer to create an aerosol that stimulates coughing, which produces a sputum sample.
- Bronchoscopy: This is a procedure that involves inserting a flexible tube through the mouth or nose and into the lungs to collect a BAL specimen.
- Tracheal aspirate: This involves inserting a catheter through the mouth or nose and into the trachea to collect a specimen.
- Gastric aspirate: This involves passing a nasogastric tube through the nose and into the stomach to collect a specimen.
- Pleural fluid aspiration: a needle is inserted into the pleural space to obtain a sample of pleural fluid
- Lumbar puncture: a needle is inserted into the spinal canal to obtain a sample of CSF
- Tissue biopsy: a sample of tissue is removed for testing using various methods, including needle biopsy or surgical excision.
- Urine specimens: Urine specimens may be collected for TB culture, particularly in cases where sputum cannot be produced or is not adequate. The collection process involves providing a clean-catch midstream urine sample in a sterile container.
It’s important to follow proper collection and handling procedures to avoid contamination and ensure accurate TB culture results.
Required Samples volume for AFB Culture:
Here’s a list of required types of samples and their volumes for TB culture:
- Sputum: At least three sputum samples should be collected over three days, with each sample being at least 2-3 mL in volume.
- Bronchoalveolar Lavage (BAL) Fluid: At least 1-2 mL of BAL fluid should be collected for TB culture.
- Gastric Lavage: At least 10 mL of gastric lavage fluid should be collected for TB culture.
- Pleural Fluid: At least 10 mL of pleural fluid should be collected for TB culture.
- Cerebrospinal Fluid (CSF): A volume of at least 1-2 mL of CSF is typically required for TB culture testing.
- Tissue Samples: A volume of at least 1-2 mL of tissue biopsy material is typically required for TB culture testing.
- Urine: At least 2-3 mL of urine should be collected for TB culture.
- Blood: At least 3-5 mL of Blood inBlood Culture Vail should be collected for TB culture.
Test Sample Preparations:
here’s some information on the test preparations required for each specimen type in TB culture:
- Sputum: Before collecting the sample, the patient should rinse their mouth with water to minimize contamination. The patient should then take a deep breath and cough deeply to produce the sputum. The sputum should be collected in a sterile, leak-proof container and transported to the laboratory as soon as possible. The laboratory will process the sputum by decontaminating it with a solution to remove other bacteria and fungi that may interfere with the TB culture. The decontaminated sample is then cultured on special media to detect the presence of TB bacteria.
- Bronchoalveolar Lavage (BAL) Fluid: The patient should undergo a bronchoscopy procedure to collect the BAL fluid. The fluid is collected in a sterile container and transported to the laboratory as soon as possible. The laboratory will process the BAL fluid by centrifugation to concentrate the TB bacteria. The concentrated sample is then cultured on special media to detect the presence of TB bacteria.
- Gastric Lavage: The patient should fast for at least 6 hours before the procedure. The patient should then undergo a gastric tube insertion to collect the lavage fluid. The fluid is collected in a sterile container and transported to the laboratory as soon as possible. The laboratory will process the lavage fluid by decontamination with a solution to remove other bacteria and fungi that may interfere with the TB culture. The decontaminated sample is then cultured on special media to detect the presence of TB bacteria.
- Pleural Fluid: The fluid is collected using a needle and syringe and transported to the laboratory as soon as possible. The laboratory will process the fluid by centrifugation to concentrate the TB bacteria. The concentrated sample is then cultured on special media to detect the presence of TB bacteria.
- Blood: Before a blood sample is taken, the healthcare provider will typically ask the patient to fast for several hours, usually 8-12 hours. This is to ensure that the results are not affected by food or drink intake. The patient should also inform the healthcare provider of any medications they are taking, as some medications can affect the results of the blood test. The patient should also inform the healthcare provider if they have any bleeding disorders or are taking blood thinners, as this may affect the ability to take a blood sample. The healthcare provider will typically clean the area where the blood will be drawn with an antiseptic solution and use a sterile needle to collect the blood sample. After the sample is collected, the healthcare provider will apply pressure to the site to stop any bleeding and may cover the area with a bandage. The blood sample will then be sent to a laboratory for testing.
- Cerebrospinal fluid (CSF): The collection of cerebrospinal fluid (CSF) is typically performed by a healthcare provider using a lumbar puncture procedure. Once the CSF sample is collected, it is transported to the laboratory for testing. In the laboratory, the CSF sample is first visually inspected for clarity and color. If the CSF appears cloudy or discolored, it may indicate the presence of an infection or other abnormality. The laboratory technician will then perform a series of tests on the CSF sample, including a cell count, protein and glucose levels, and culture for bacteria, fungi, and viruses. The CSF sample may also be tested for other markers of infection or inflammation, such as white blood cell count or cytokine levels. The laboratory may use additional techniques, such as polymerase chain reaction (PCR) or antibody tests, to detect specific pathogens or antibodies in the CSF sample. The results of the CSF tests can help diagnose a variety of conditions, including meningitis, encephalitis, and other neurological disorders.
- Biopsy: A biopsy is a medical procedure in which a small piece of tissue is removed from the body for examination under a microscope. Before a biopsy, the healthcare provider will typically inform the patient about the procedure and obtain informed consent. Depending on the location of the biopsy, the patient may need to fast or stop taking certain medications prior to the procedure. The healthcare provider will clean the area where the biopsy will be taken with an antiseptic solution and may administer local anesthesia to numb the area. A small incision is then made, and a tissue sample is removed using a specialized instrument, such as a needle or forceps. The tissue sample is then transported to the laboratory for testing. In the laboratory, the tissue sample is first examined visually for color and consistency. The laboratory technician will then perform a series of tests on the tissue sample, including a histological examination, which involves staining the tissue to examine its cellular structure under a microscope. The results of the biopsy tests can help diagnose a variety of conditions, including cancer and other diseases.
- Bronchial washings: Bronchial washings are obtained by a healthcare provider during a bronchoscopy procedure. During the procedure, the healthcare provider will pass a flexible bronchoscope through the patient’s mouth or nose and into the lungs. Once the bronchoscope is in place, the healthcare provider will use a syringe to inject a sterile solution into the airways and then suction it back out, collecting the bronchial washings in a sterile container. The sample is then transported to the laboratory for testing. In the laboratory, the sample is first examined visually for color and consistency. The laboratory technician will then perform a series of tests on the bronchial washing sample, including a culture for bacteria, fungi, and viruses. The sample may also be examined under a microscope to look for the presence of abnormal cells or other signs of infection or inflammation. The results of the bronchial washing tests can help diagnose a variety of conditions, including infections, lung cancer, and other lung diseases.
- Urine: Before collecting a urine sample, the healthcare provider will typically provide the patient with a sterile container for collecting the sample. The patient should clean their genital area with a mild soap and water before collecting the urine sample. It is important to collect a midstream urine sample, which involves starting to urinate, stopping briefly, and then collecting the middle portion of the urine stream in the sterile container. The first and last portions of the urine stream are not collected, as they may contain bacteria or other contaminants. The patient should avoid touching the inside of the container or the lid to prevent contamination. The sample should be promptly transported to the laboratory for testing, ideally within two hours of collection. In the laboratory, the urine sample is first examined visually for color and clarity. The laboratory technician will then perform a series of tests on the urine sample, including a dipstick test to measure the presence of various substances in the urine, such as protein, glucose, and blood. The urine sample may also be cultured for bacteria if an infection is suspected. The results of the urine tests can help diagnose a variety of conditions, including urinary tract infections, kidney diseases, and diabetes.
It’s important to note that the laboratory will perform additional tests to confirm the presence of TB bacteria and to determine the antibiotic susceptibility of the bacteria.
- World Health Organization. (2014). Laboratory diagnosis of tuberculosis by sputum microscopy: the handbook. Geneva: World Health Organization. https://www.who.int/publications/i/item/9789241548748
- Centers for Disease Control and Prevention. (2013). Laboratory diagnosis of tuberculosis: laboratory biosafety guidelines. Atlanta, GA: Centers for Disease Control and Prevention. https://www.cdc.gov/mmwr/preview/mmwrhtml/rr6210a1.htm
- American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America. (2017). Diagnosis of tuberculosis in adults and children. Clinical Infectious Diseases, 64(2), e1-e33. https://doi.org/10.1093/cid/ciw778
- Lumb, R., van der Zalm, M. M., & Cirillo, D. M. (2015). Diagnosis of pulmonary tuberculosis: recent advances and diagnostic algorithms. The Indian Journal of Medical Research, 141(1), 7–16. https://doi.org/10.4103/0971-5916.154481
- World Health Organization. (2016). Treatment of tuberculosis: guidelines. Geneva: World Health Organization. https://www.who.int/publications/i/item/9789241549684
Possible References Used