isdh: tuberculin skin test screening and treatment of latent tb infection

8/10/2019 ISDH: Tuberculin Skin Test Screening and Treatment of Latent TB Infection

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unnecessary diagnostic evaluation and treatment.

School-based screening for TB among children was started in the 1950s when infection and

disease rates were higher than at the present time.

Broad-based school testing involves screening large numbers of low-risk children and the

majority of children who have TB are preschool age.

Generalized screening of school children as a public health measure is not a cost-effective

method of detecting or preventing cases of childhood TB and should be discontinued.

Who should receive treatment for LTBI?

Regardless of age, persons who fall into one or more of the following high-risk categories with a

positive skin test, and who have not previously received treatment, should be treated unlesscontraindicated (see below):

close contacts of a person with infectious TB (TST considered positive with !5mm

induration)

persons with HIV infection (TST considered positive with !5mm induration)

organ transplant patients, or patients with other immunosuppressive disorders (TST

considered positive with !5mm induration)

persons whose chest x-ray shows stable fibrotic lesions consistent with old, healed MTB and

a history of inadequately treated TB or no prior history of treatment for TB (TST considered

positive with !5mm induration)

injection drug userspersons with clinical conditions that make them high-risk, e.g. diabetes mellitus, certain

forms of cancer, silicosis, end-stage renal disease, substance abusers

recent tuberculin skin test converters (!10mm increase within the past two years)

persons born in countries where TB is common

mycobacteriology laboratory personnel

residents and employees of high-risk congregate settings

children younger than 4 years of age

children and adolescents exposed to adults in high-risk groups

persons with recent travel to an area with high rates of TB

Some contacts to infectious TB cases have medical conditions that increase their risk ofprogression to active disease if they are infected. Persons with high-risk medical conditions (e.g.,

HIV +, children < 4 years of age, immunosuppression) who have had active disease ruled out but

whose initial TST is < 5 mm of induration, should be placed on treatment for LTBI until LTBI is

ruled out. If a second TST placed 10 weeks after last contact with the source case is still < 5 mm,

treatment may be stopped. If it is !5 mm, continue the full course of treatment.

What is the recommended treatment regimen for LTBI?

Isoniazid for 9 months, regardless of age or HIV status, is the preferred regimen. Isoniazid may be

given to HIV-negative adults for 6 months if treatment for 9 months is not possible. PZA and

rifampin for 2 or 3 months for adults only is no longer recommended for general use due to an

unacceptably high risk of hepatitis. Consult with a TB expert before prescribing this regimen.

Rifampin for 4 months for adults or 6 months for children is an alternate regimen that may be

prescribed in certain circumstances, such as exposure to an isoniazid-resistant case. Dosages for

all regimens are the same as for active disease. The alternate short-course regimens are strictly

second-line recommendations and should not be used routinely in place of the isoniazid regimens.

persons with active hepatitis

persons with end-stage liver disease

pregnancy (therapy is usually delayed until after delivery)

major adverse medication reactions

previousadequate treatment for LTBI or active disease

What are the current standards for the evaluation and monitoring of treatment (LTBI)?

Baseline laboratory testing is not routinely indicated for all patients at the start of treatment

for LTBI.

Recent data indicate that baseline testing is no longer routinely indicated in persons older

than 35 years of age.


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isdh: tuberculin skin test screening and treatment of latent tb infection

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