Latent tuberculosis

As of 2023, it is estimated that one quarter of the world's population has latent or active TB,{{Cite web |date=29 October 2024 |title=10 facts on tuberculosis |url=https://www.who.int/news-room/facts-in-pictures/detail/tuberculosis |access-date=2025-03-15 |website=World Health Organization |language=en}} with TB estimated to have newly infected 10.8 million people per year.{{Cite web |date=14 March 2025 |title=Tuberculosis (TB) |url=https://www.who.int/news-room/fact-sheets/detail/tuberculosis |access-date=2025-03-14 |website=World Health Organization |language=en}}

As of 2023, it is estimated that one quarter of the world's population has latent or active TB,{{Cite web |date=29 October 2024 |title=10 facts on tuberculosis |url=https://www.who.int/news-room/facts-in-pictures/detail/tuberculosis |access-date=2025-03-15 |website=World Health Organization |language=en}} with TB estimated to have newly infected 10.8 million people per year.{{Cite web |date=14 March 2025 |title=Tuberculosis (TB) |url=https://www.who.int/news-room/fact-sheets/detail/tuberculosis |access-date=2025-03-14 |website=World Health Organization |language=en}}

The spread of TB is uneven throughout the world, with approximately 80% of the population in many Asian and African countries testing positive on tuberculin tests, while only 5–10% of the US population tests positive.{{cite book|year=2007 |title=Robbins Basic Pathology |publisher=Saunders Elsevier |pages=516–522 |isbn=978-1-4160-2973-1 |author=Kumar V. |author2=Abbas A. K. |author3=Fausto N. |author4=Mitchell R. N. }}

The spread of TB is uneven throughout the world, with approximately 80% of the population in many Asian and African countries testing positive on [[Mantoux test|tuberculin tests]], while only 5–10% of the US population tests positive.{{cite book|year=2007 |title=Robbins Basic Pathology |publisher=Saunders Elsevier |pages=516–522 |isbn=978-1-4160-2973-1 |author=Kumar V. |author2=Abbas A. K. |author3=Fausto N. |author4=Mitchell R. N. }}

==Transmission==

==Transmission==

====Mantoux test====

====Mantoux test====

:''See: [[Mantoux test]]''

:''See: [[Mantoux test]]''

The Mantoux test is now standardized by the World Health Organization ([[World Health Organization|WHO]]). Tuberculin at 0.1 milliliter (mL; 100 units/mL), which delivers a dose of 5 units, is given by [[intradermal]] injection into the surface of the lower forearm ([[subcutaneous injection]] results in false negatives). A waterproof ink mark is drawn around the injection site so as to avoid difficulty of finding it later if the level of reaction is small. The test is read 48 to 72 hours later.{{cite web |url=https://www.cdc.gov/tb/topic/testing/default.htm |title=CDC | TB | Testing & Diagnosis |publisher=Cdc.gov |access-date=2015-10-05 |archive-date=2022-07-05 |archive-url=https://web.archive.org/web/20220705104338/https://www.cdc.gov/tb/topic/testing/default.htm |url-status=live }} The area of [[induration]] (NOT of [[erythema]]) is measured [[Transverse plane|transversely]] across the forearm (left to right, not up and down) and recorded to the nearest millimeter (mm).[http://health.nytimes.com/health/guides/test/ppd-skin-test/] {{webarchive|url=https://web.archive.org/web/20131021150709/http://health.nytimes.com/health/guides/test/ppd-skin-test/|date=October 21, 2013}}

The Mantoux test is now standardized by the World Health Organization ([[World Health Organization|WHO]]). Tuberculin at 0.1 milliliter (mL; 100 units/mL), which delivers a dose of 5 units, is given by [[intradermal]] injection into the surface of the lower forearm ([[subcutaneous injection]] results in false negatives). A waterproof ink mark is drawn around the injection site so as to avoid difficulty of finding it later if the level of reaction is small. The test is read 48 to 72 hours later.{{cite web |url=https://www.cdc.gov/tb/topic/testing/default.htm |title=CDC | TB | Testing & Diagnosis |publisher=Cdc.gov |access-date=2015-10-05 |archive-date=2022-07-05 |archive-url=https://web.archive.org/web/20220705104338/https://www.cdc.gov/tb/topic/testing/default.htm |url-status=live }} The area of [[induration]] (NOT of [[erythema]]) is measured [[Transverse plane|transversely]] across the forearm (left to right, not up and down) and recorded to the nearest millimeter (mm).[https://health.nytimes.com/health/guides/test/ppd-skin-test/] {{webarchive|url=https://web.archive.org/web/20131021150709/http://health.nytimes.com/health/guides/test/ppd-skin-test/|date=October 21, 2013}}

====Heaf test====

====Heaf test====