tuberculin-skin testing (TST)

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Indications

Contraindications

* once positive, test remains positive after treatment for active tuberculosis or latent tuberculosis

Procedure

* .Purified-protein derivative is the antigen commonly used in tuberculin-skin testing.

* CDC's Mantoux Tuberculin Skin Test Video[9]

Interpretation

Criteria for a positive TST are:

* includes > 15 mg/day of prednisone for > 4 weeks[2] or other immunosuppressive therapy

induration is measured, not the erythema[2]

Sensivitity of tuberculin skin testing for latent TB is close to 100%[3]

20-25% of patients with active tuberculosis may have a negative skin test.[8]

Test conversion among healthcare workers is unrelated to exposure to tuberculosis

If controls are used with PPD, mumps is used as a positive control, Candida is used as a negative control.

BCG vaccination should not affect interpretation of TST.

BCG vaccination may cause false positive[2]

Atypical Mycobacteria may cause false positives[2] ;

* CDC's Mantoux Tuberculin Skin Test Video[9]

Complications

  • 5% of individuals with recent conversion of tuberculin skin testing (TST) will develop active disease within 1 year if left untreated
    • adequate treatment reduces this risk*

* Contrary to popular belief, false positives occur, subjecting patients to unnecessary prolonged treatment with antibiotics

  • patients with false positive PPD may test negative on retesting

Management

Also see chemoprophylaxis for tuberculosis

More general terms

Additional terms

References

  1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015
    Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. 3.0 3.1 American Thoracic Society Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection http://www.thoracic.org/sections/publications/statements/pages/mtpi/latenttb1-27.html
  4. 4.0 4.1 4.2 Geriatric Review Syllabus, 7th edition Parada JT et al (eds) American Geriatrics Society, 2010
    Geriatric Review Syllabus, 11th edition (GRS11) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2022
  5. 5.0 5.1 Centers for Disease Control and Prevention Targeted tuberculin testing and treatment of latent tuberculosis infection. American Thoracic Society. MMWR Recomm Rep. 2000 Jun 9;49(RR-6):1-51. PMID: https://www.ncbi.nlm.nih.gov/pubmed/10881762
  6. Centers for Disease Control and Prevention National Shortage of Purified-Protein Derivative Tuberculin Products. MMWR. April 26, 20013 http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6216a5.htm
  7. Dorman SE et al. Interferon-gamma release assays and tuberculin skin testing for diagnosis of latent tuberculosis infection in healthcare workers in the United States. Am J Respir Crit Care Med 2014 Jan 1; 189:77 PMID: https://www.ncbi.nlm.nih.gov/pubmed/24299555
  8. 8.0 8.1 Dagogo-Jack I, Vaidya A, Geller B, Baden LR, Stone R. A Man with Fever, Cough and Rash N Engl J Med 2014 371:e11. August 21, 2014 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/25140977 <Internet> http://www.nejm.org/doi/full/10.1056/NEJMimc1310796
  9. 9.0 9.1 9.2 Centers for Disease Control and Prevention Mantoux Tuberculin Skin Test Video https://www.youtube.com/watch?v=Qzt-qGgglo0
  10. Centers for Disease Control and Prevention Fact Sheets. Tuberculin Skin Testing https://www.cdc.gov/tb/publications/factsheets/testing/skintesting.htm

Patient information

tuberculin skin testing patient information