Tuberculosis test, cell mediated immunity antigen response measurement; gamma interferon
CPT4 code
Name of the Procedure:
Tuberculosis Test, Cell Mediated Immunity Antigen Response Measurement; Gamma Interferon
Summary
This test measures the immune system's response to Mycobacterium tuberculosis by detecting the release of interferon-gamma, a type of protein that white blood cells produce in response to TB antigens. It is a blood test used to diagnose tuberculosis (TB) infection.
Purpose
The TB Gamma Interferon test is used to detect latent or active tuberculosis infection. The goal is to identify individuals with TB so they can receive appropriate treatment to prevent the progression of the disease and reduce the risk of spreading the infection to others.
Indications
- Persistent cough lasting more than 2-3 weeks
- Unexplained weight loss
- Night sweats
- Fever
- Having close contact with someone diagnosed with TB
- Positive TB skin test results requiring confirmation
Preparation
- No fasting or special medications are typically required beforehand.
- Inform the healthcare provider about any medications, allergies, or medical conditions.
- A preliminary TB skin test may be conducted if it hasn't been done previously.
Procedure Description
- A small sample of blood is drawn from a vein in your arm.
- The blood sample is then mixed with TB antigens in the laboratory.
- The mixture is incubated and the response of the immune cells is measured by the amount of interferon-gamma released.
- Results are analyzed and interpreted by a healthcare professional.
Duration
The blood draw takes about 5-10 minutes, but the overall turnaround time for results may be a few days to a week.
Setting
The procedure is typically performed in an outpatient clinic, hospital, or specialized laboratory.
Personnel
- Phlebotomist or nurse to draw the blood sample.
- Laboratory technicians to analyze the results.
- Physician or healthcare provider to interpret and discuss the results with the patient.
Risks and Complications
- Minor discomfort or bruising at the blood draw site.
- Slight risk of infection at the puncture site.
- Rarely, fainting or feeling light-headed.
Benefits
- Accurate detection of TB infection.
- Non-invasive with minimal discomfort.
- Faster and more specific than traditional TB skin tests.
- Helps in early identification and treatment to prevent disease spread.
Recovery
- Minimal to no recovery time needed.
- Patients can resume normal activities immediately after the blood draw.
- Follow-up appointment may be scheduled to discuss results and next steps.
Alternatives
- TB skin test (Mantoux test): An older method that may require multiple visits and has a higher false-positive rate.
- Chest X-ray: Used to confirm active TB, particularly in those with a positive skin test or Gamma Interferon test.
- Sputum test: Tests for the presence of TB bacteria in the mucus from the lungs.
Patient Experience
- Mild discomfort during the blood draw.
- Most patients experience minimal pain, and the procedure is quick.
- Some patients might feel anxious about the blood draw and should inform their healthcare provider if they have concerns.