Infectious agent detection by nucleic acid (DNA or RNA); Mycobacteria tuberculosis, amplified probe technique
CPT4 code
Name of the Procedure:
Infectious Agent Detection by Nucleic Acid (DNA or RNA); Mycobacteria tuberculosis, Amplified Probe Technique
Common name(s): TB DNA/RNA Detection, Nucleic Acid Amplification Test (NAAT) for TB
Summary
This procedure involves testing a patient's sample, such as sputum, for the DNA or RNA of Mycobacterium tuberculosis. It uses a technique that amplifies the genetic material of the bacteria, making it easier to detect even small amounts of the organism.
Purpose
This test is used to diagnose tuberculosis (TB) infection. It helps in detecting TB more rapidly and accurately compared to traditional methods, which can take weeks.
Indications
- Persistent cough lasting more than three weeks
- Coughing up blood
- Unexplained weight loss
- Night sweats
- Fever and chills
- History of exposure to TB
- Suspected TB in immunocompromised patients, such as those with HIV
Preparation
- No specific fasting or medication adjustments are usually required.
- The patient may need to provide a sputum sample or other samples as directed by the healthcare provider.
Procedure Description
- The patient provides a sample, typically sputum.
- The sample is treated to release the bacterial DNA or RNA.
- The released nucleic acids are amplified using specialized enzymes.
- Probes specific to Mycobacterium tuberculosis DNA or RNA are added, which bind to the target sequences if present.
- Results are analyzed to determine the presence of TB bacteria.
Equipment used includes:
- Thermal cycler for DNA amplification
- Fluorescent or colorimetric probes for detection
No anesthesia or sedation is typically required for this non-invasive test.
Duration
The procedure itself takes a few hours, but results are often available within 24-48 hours.
Setting
The procedure is usually performed in a specialized laboratory.
Personnel
- Laboratory technicians
- Molecular biologists
- Microbiologists
Risks and Complications
- Minimal risk associated with sample collection.
- Rare risk of false positives or negatives, leading to misdiagnosis.
Benefits
- Rapid and accurate detection of TB.
- Helps in starting appropriate treatment sooner, improving patient outcomes.
- More sensitive and specific compared to traditional culture methods.
Recovery
- No recovery period is required as it is a diagnostic test.
- Normal activities can be resumed immediately after sample collection.
Alternatives
- Sputum culture (takes longer, less sensitive)
- Tuberculin skin test (TST)
- Interferon-gamma release assays (IGRAs)
- Chest X-rays and CT scans
Patient Experience
- The patient might experience mild discomfort when providing a sputum sample.
- Pain management is generally not required, but instructions for hydration and techniques to aid sputum production may be given.
By understanding the procedure, patients can be better prepared and more comfortable during the diagnostic process.