Table 4.

Recommendations for the use of IGRA-testing^* and preventive chemotherapy against active tuberculosis in low-incidence countries according to the number needed to treat to prevent one case of TB.

Recommended	Conditionally recommended	Not recommended
People living with HIV (especially with ongoing viral replication)a	Solid organ transplant recipientsc	Health-care workersd
Child and adult contacts of pulmonary TB casesa	Stem- cell transplant recipientsc	Illicit drug userse
Migrants originating from high incidence countriesa	Patients with chronic renal failurec	Homeless peoplee
Patients receiving tumor necrosis factor (TNF)- antagonist therapyb	HIV-negative patients with other immunodeficiencies not mentioned abovec	Patients with diabetes mellituse
	Patients with silicosisc	Prisonerse
		People with alcohol abusee
		Tobacco smokerse
		Underweight peoplee

^anumber needed to treat to prevent a case of TB of < 50;

^bnumber needed to treat to prevent a case of TB of > 50 but justified by severity of TB disease;

^cnumber needed to treat to prevent a case of TB of > 100; at least one additional risk factors for LTBI should be present;

^dnumber needed to treat to prevent a case of TB of >> 100 or

^enot known but perceived to be high; unless other factors leading to strong or conditional recommendations are present;

*the best method is to combine IGRA/TST results with a risk/benefit assessment performed by algorithms [57].