Mantoux Test / TST Interpretation (TB)
Tuberculin Skin Test (Mantoux) interpretation for latent TB infection (LTBI) screening. Induration threshold varies by risk group per NICE / WHO.
Score interpretation
TST negative: Latent TB infection unlikely in current risk context.
→ No treatment required. If TST negative but high-risk exposure: repeat TST 8–10 weeks after last exposure (window period). Consider IGRA (interferon-gamma release assay — QuantiFERON or T-SPOT) for more specific testing, especially if BCG vaccinated.
Borderline TST result. IGRA recommended to differentiate LTBI from BCG response.
→ Send IGRA (QuantiFERON-TB Gold or T-SPOT.TB). If IGRA positive: treat as LTBI (see below). If IGRA negative: likely BCG effect — no treatment. Chest X-ray to exclude active TB before treatment. NICE NG33.
TST strongly positive. LTBI likely, especially in high-risk patient.
→ Confirm with IGRA. CXR to exclude active TB (active TB must be treated differently). Exclude active TB symptoms: cough > 3 weeks, haemoptysis, night sweats, weight loss, fever. LTBI treatment: 3HR (3 months isoniazid + rifampicin) or 6H (6 months isoniazid). HIV testing. Contact trace family if new diagnosis. Notify Public Health England / HPSC. NICE NG33.
Interpretation bands for the Mantoux / TST. Apply clinical judgement and local guidance.
References
- NICE NG33. Tuberculosis: prevention, diagnosis, management and service organisation. 2016 (updated 2019).
- WHO. Latent tuberculosis infection: updated and consolidated guidelines for programmatic management. 2018.
Related
Curated clinical cross-links plus same-class fallbacks.
- Tetracosactide · Synthetic ACTH (short Synacthen test)
- Urea (13C) · 13C-urea breath test
- Isoniazid · Anti-Tuberculosis Antibiotic
- Tuberculin purified protein derivative · Mycobacterial antigen for delayed-type hypersensitivity testing
- Aminosalicylic Acid (Para-aminosalicylic acid, PAS) · Antimycobacterial (Anti-tuberculosis Agent)
- Infective Endocarditis · ESC 2023 Infective Endocarditis Guidelines; NICE NG41
- Eczema Herpeticum · BAD; NICE CKS
- Suspected Bacterial Meningitis (Adult) · NICE NG240 (2024); NICE NG143 (paeds)
- Clostridioides difficile Colitis · NICE NG199 (2021); IDSA/SHEA 2021
- Returning Traveller — Fever · NaTHNaC; PHE; ESCMID 2018
- Malaria — Diagnosis & Management · PHE 2016; WHO 2023
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.