TPP: For a test predicting progression from tuberculosis (TB) infection to active disease

A test predicting progression from tuberculosis infection to active disease.

Minimum/Acceptable: Test that can be used to predict risk of progression to active TB from TB infection within the next 2 years. As this test may also be positive in patients with active TB, identification of these individuals needs to be done by a highly sensitive test. Preferred/Optimal/Ideal: Test that can be used to predict risk of progression to active TB from TB infection (TBI) within the next 2 years and provides a quantitative result that correlates with the risk of progression. The test result should decrease or revert to negative with treatment and thus allow an assessment of treatment success or cure and consequentially also reinfection.

Minimum/Acceptable: Asymptomatic individuals who have increased likelihood of exposure to a person with active TB (e.g. close contacts) and individuals with conditions that predispose to progression of TBI to active disease (HIV infection, diabetes, chronic renal failure, chronic medical illness, recent TST converters, children < 5 years of age, and persons receiving anti-TNF). Preferred/Optimal/Ideal: Asymptomatic individuals who have increased likelihood of exposure to a person with active TB (e.g. close contacts) and individuals with conditions that predispose to progression of TBI to active disease (HIV infection, diabetes, chronic renal failure, chronic medical illness, recent TST converters, children < 5 years of age, and persons receiving anti-TNF).

Minimum/Acceptable: Whole blood by phlebotomy (or subpopulation of cells if simple processing included) / sputum. Preferred/Optimal/Ideal: Capillary whole blood (finger prick sample) / saliva / urine / stool / breath.

Minimum/Acceptable: Referral facilities with some laboratory facilities. Preferred/Optimal/Ideal: Health post.

Clinical sensitivity:: Minimum/Acceptable: For progression to active TB, >=75%. Preferred/Optimal/Ideal: For progression to active TB, >=90%. Clinical specificity:: Minimum/Acceptable: For risk of progression to active TB, >=75%. Preferred/Optimal/Ideal: For risk of progression to active TB, >=90%. Time to results:: Minimum/Acceptable: 2-5 days. Preferred/Optimal/Ideal: <24 hours.

Stability and storage:: Minimum/Acceptable: 12 months at 30 °C, 70% humidity, cold chain required for transport. Preferred/Optimal/Ideal: 24 months at 40 °C, 90% humidity, should be able to tolerate stress during transport (3 days at 50 °C).

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