💉 Tuberculin, Purified Protein Derivative (PPD)
📄 Description:
Tuberculin PPD is a diagnostic agent used in the Mantoux tuberculin skin test (TST) to detect latent or active tuberculosis (TB) infection by evaluating the body’s immune response to Mycobacterium tuberculosis proteins.
- Form: Injectable solution
- Strength: Typically 5 TU (tuberculin units) in 0.1 mL
- Route: Intradermal injection (forearm skin)
📝 Prescription:
- Type: Prescription or Government-regulated (depending on country)
- Use: Diagnostic (not therapeutic)
- Indication: Screening for TB infection in high-risk individuals (e.g., healthcare workers, immunocompromised patients, contacts of TB cases)
🌿 Nature:
- Biological extract from culture filtrates of Mycobacterium tuberculosis
- Not live, not infectious
- Used solely for diagnostic purposes
✅ Advantages:
- Quick, inexpensive test for TB exposure
- Widely accepted and used globally
- Helps identify candidates for further testing (e.g., chest X-ray or IGRA)
- Can aid in public health TB control efforts
⚠️ Precautions:
- Should not be administered to individuals with:
- A known TB diagnosis or previous strong positive TST
- Severe skin conditions at the injection site
- Interpretation must consider:
- Patient history
- BCG vaccination
- Immune status
- False positives possible with BCG vaccine or exposure to non-TB mycobacteria
- False negatives possible in:
- Very recent TB infection (<8 weeks)
- Immunocompromised states (e.g., HIV, corticosteroids)
- Very young or elderly individuals
🧊 Storage:
- Store in refrigerator at 2°C to 8°C
- Do not freeze
- Protect from light and heat
- Use within expiry and handle under sterile conditions
📦 Common Packaging:
- Multidose vials (usually 1.5 mL or 5 mL)
- Vial strength: Each 0.1 mL dose contains 5 TU
- Clearly labeled with batch number, expiry date, storage instructions
👨⚕️ Patient Advice (Short Points):
- Inform your healthcare provider about any past TB test or BCG vaccine.
- The test involves a small injection just under the skin of your forearm.
- Do not scratch or press the site after the injection.
- Return to the clinic in 48–72 hours for result interpretation.
- A raised, hard area at the site may indicate TB exposure.
- Keep the site clean and dry—avoid applying creams or bandages.
- Follow-up tests like chest X-rays may be needed based on the result.
- No treatment is given based solely on this test—it’s a screening tool.