Targeted Testing and Treatment of Latent Tuberculosis Infection 

Text Only Version 

Targeted Testing and Treatment of Latent Tuberculosis Infection 

Slide 1: Targeted Tuberculosis (TB) Testing and Treatment of Latent Tuberculosis Infection 

September 2016

National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention 

Division of Tuberculosis Elimination 

Slide 2: Targeted TB Testing and Treatment of Latent TB Infection 

As TB disease rates in the United States decrease, finding and treating persons at high risk for latent TB 

infection (LTBI) has become a priority. 

Targeted TB testing is used to focus program activities and provider practices on groups at the highest 

risk for TB. 

Treatment of LTBI substantially reduces the risk that persons infected with M. tuberculosis will progress 

to TB disease. 

Slide 3: Latent TB Infection (LTBI) 

LTBI is the presence of M. tuberculosis organisms (tubercle bacilli) without signs and symptoms or 

radiographic or bacteriologic evidence of TB disease. 

Slide 4: LTBI vs. Pulmonary TB Disease – 1 

Latent TB Infection 

Positive TST* or IGRA† result

Chest radiograph normal 

Pulmonary TB Disease 

TST or IGRA is usually positive 

Chest radiograph is usually abnormal 

*tuberculin skin test

† Interferon-Gamma Release Assay

Slide 5: LTBI vs. Pulmonary TB Disease – 2 

Latent TB Infection 

No symptoms or physical findings suggestive of TB disease 
If done, respiratory specimens are smear and culture negative 

Pulmonary TB Disease 

Symptoms may include one or more of the following: fever, cough, night sweats, weight loss, fatigue, 

hemoptysis, decreased appetite 

Respiratory specimens are usually culture positive (smear positive in about 50% of patients) 

Slide 6: Targeted TB Testing 

Essential TB prevention and control strategy 

Detects persons with LTBI who would benefit from treatment 

De-emphasizes testing of groups that are not at high risk for TB 

Can help reduce the waste of resources and prevent inappropriate treatment 

Slide 7: Treatment of LTBI – Milestones – 1

For more than 3 decades, an essential component of TB prevention and control in the United States has 

been the treatment of persons with LTBI to prevent TB disease. 

Slide 8: Treatment of LTBI – Milestones – 2

1965: American Thoracic Society (ATS) recommends treatment of LTBI for those with previously 

untreated TB, tuberculin skin test (TST) converters, and young children. 

1967: Recommendations expanded to include all TST positive reactors (≥ 10 mm).

Slide 9: Treatment of LTBI – Milestones – 3

1974: CDC and ATS guidelines established for pretreatment screening to decrease risk of hepatitis 

associated with treatment 

Treatment recommended for persons ≤ 35 years of age

Slide 10: Treatment of LTBI – Milestones – 4

1983: CDC recommends clinical and laboratory monitoring of persons ≥ 35 who require treatment for 

LTBI 

1998: CDC recommends 2 months of rifampin (RIF) plus pyrazinamide (PZA) as an option for HIVinfected patients (later changed) 

Slide 11: Treatment of LTBI – Milestones – 5

2000: CDC and ATS issue updated guidelines for targeted testing and LTBI treatment1 

9-month regimen of isoniazid (INH) is preferred
2-month regimen of RIF and PZA and a 4 month regimen of RIF recommended as options (later

changed)

1 MMWR(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/rr4906a1.htm) June 9, 2000; 49(No. RR6)(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/rr4906a1.htm) 

Slide 12: Treatment of LTBI – Milestones – 6 

2001: Owing to liver injury and death associated with 2-month regimen of RIF and PZA, use of this 

option de-emphasized in favor of other regimens2 

2003: 2-month regimen of RIF and PZA generally not recommended — to be used only if the potential 

benefits outweigh the risk of severe liver injury and death3 

2MMWR(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/mm5034a1.htm) August 31, 2001; 50(34): 

733-735(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/mm5034a1.htm)

3MMWR(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/mm5231a4.htm) August 8, 2003; 52(31): 

735-739(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/mm5231a4.htm)

Slide 13: Treatment of LTBI – Milestones – 7 

2011: CDC recommends 12-doses (3 months) of isoniazid (INH) and rifapentine (RPT) as an option 

equal to the standard 9-month INH regimen for certain groups*

2016: U.S. Preventive Services Task Force recommends testing for TB as a part of standard preventive 

care for certain at-risk groups**

*Recommendations for Use of an Isoniazid–Rifapentine Regimen with Direct Observation to Treat

Latent Mycobacterium tuberculosis Infection

Slide 14: Identifying Risk Factors That Lead to Development of TB Disease 

Slide 15: Persons at Risk for Developing TB Disease 

Persons at high risk for developing TB disease fall into 2 categories: 

Those who have an increased likelihood of exposure to persons with TB disease 

Those with clinical conditions that increase their risk of progressing from LTBI to TB disease 

Slide 16: Increased Likelihood of Exposure to Persons with TB Disease 

Persons at risk for exposure to persons with TB disease include: 

Close contacts to person with infectious TB 

Residents and employees of high-risk congregate settings (e.g., correctional facilities, homeless shelters, 

health care facilities) 

Recent immigrants from TB-endemic regions of the world (within 5 years of arrival to the United States) 

Slide 17: Increased Risk for Progression to TB Disease – 1 
Persons more likely to progress from LTBI to TB disease include: 

HIV-infected persons 

Those with a history of prior, untreated TB or fibrotic lesions on chest radiograph 

Children ≤ 5 years with a positive TST

Slide 18: Increased Risk for Progression to TB Disease – 2 

Persons more likely to progress from LTBI to TB disease include: 

Underweight or malnourished persons 

Substance abusers (such as smoking, alcohol abuse, or injection drug use)

Those receiving TNF-α antagonists for treatment of rheumatoid arthritis or Crohn’s disease

Slide 19: Increased Risk for Progression to TB Disease – 3 

Persons more likely to progress from LTBI to TB disease include: 

Those with certain medical conditions such as: 

Silicosis 

Diabetes mellitus 

Chronic renal failure or on hemodialysis 

Solid organ transplantation (e.g., heart, kidney) 

Carcinoma of head or neck 

Gastrectomy or jejunoilial bypass 

Slide 20: Testing for M. tuberculosis Infection 

Slide 21: Testing for M. tuberculosis Infection 

There are two testing methods available for the detection of M. tuberculosis infection in the United 

States: 

Mantoux tuberculin skin test (TST) 

Interferon-gamma release assays (IGRA) 

These tests do not exclude LTBI or TB disease 

Decisions about medical and public health management should include other information, and not rely 

only on TST or IGRA results 
Slide 22: Mantoux Tuberculin Skin Test 

Skin test that produces delayed-type hypersensitivity reaction in persons with M. tuberculosis infection 

TST is useful for: 

Determining how many people in a group are infected (e.g., contact investigation) 

Examining persons who have symptoms of TB disease 

Multiple puncture tests (e.g., Tine Test) are inaccurate and not recommended 

Slide 23: Administering the TST 

Inject 0.1 ml of 5 TU PPD tuberculin solution intradermally on volar surface of lower arm using a 27-

guage needle 

Produce a wheal 6 to 10 mm in diameter 

[Image: Drawing of gloved hands holding a tuberculin syringe and injecting PPD into an arm. The 

drawing shows a discrete, pale elevation of the skin (wheal) has been formed.] 

Slide 24: Reading the TST – 1 

Measure reaction in 48 to 72 hours 

Measure induration, not erythema 

Record reaction in millimeters, not “negative” or “positive”

Ensure trained health care professional measures and interprets the TST 

[Image: Drawing of a hand holding a TST ruler and measuring the diameter of an induration. Only the 

induration is being measured; this is the correct way to read the TST reaction.] 

Slide 25: Reading the TST – 2 

Educate patient and family regarding significance of a positive TST result 

Positive TST reactions can be measured accurately for up to 7 days 

Negative reactions can be read accurately for only 72 hours 

Slide 26: TST Interpretation – 1

≥ 5 mm induration is interpreted as positive in

HIV-infected persons 

Close contacts to an infectious TB case 

Persons with chest radiographs consistent with prior untreated TB 
Slide 27: TST Interpretation – 2

≥ 5 mm induration is interpreted as positive in

Organ transplant recipients 

Other immunosuppressed patients (e.g. , those taking the equivalent of > 15 mg/d of prednisone for 1 

month or those taking TNF-α antagonists)

Slide 28: TST Interpretation – 3

≥ 10 mm induration is interpreted as positive in

Recent immigrants 

Injection drug users 

Residents or employees of congregate settings 

Mycobacteriology laboratory personnel 

Slide 29: TST Interpretation – 4

≥ 10 mm induration is interpreted as positive in

Persons with clinical conditions that place them at high risk 

Children < 4 years; infants, children, and adolescents exposed to adults at high-risk 

Slide 30: TST Interpretation – 5

≥ 15 mm induration is interpreted as positive in 

Persons with no known risk factors for TB. 

Although skin testing programs should be conducted only among high-risk groups, certain individuals 

may require TST for employment or school attendance. Diagnosis and treatment of LTBI should always 

be tied to risk assessment. 

Slide 31: Factors That May Cause False-Positive TST Reactions 

Nontuberculous mycobacteria 

Reactions caused by nontuberculous mycobacteria are usually £10 mm of induration 

BCG vaccination 

Reactivity in BCG vaccine recipients generally wanes over time; positive TST result is likely due to TB 

infection if risk factors are present 
Slide 32: Factors That May Cause False-Negative TST Reactions -1

Anergy 

Inability to react to a TST because of a weakened immune system 

Usefulness of anergy testing in TST-negative persons who are HIV infected has not been demonstrated 

Slide 33: Factors That May Cause False-Negative TST Reactions – 2

Recent TB Infection 

Defined as less than 10 weeks after exposure 

Very young age 

Newborns (< 6 months) 

Slide 34: Factors That May Cause False-Negative TST Reactions – 3

Live virus vaccination 

For example, measles or smallpox 

Can temporarily suppress TST reactivity 

Overwhelming TB Disease 

Poor TST administration technique 

For example, TST injection too shallow or too deep, or wheal is too small 

Slide 35: Boosting 

Some people with LTBI may have a negative skin test reaction when tested years after infection because 

of a waning response. 

An initial skin test may stimulate (boost) the ability to react to tuberculin. 

Positive reactions to subsequent tests may be misinterpreted as new infections rather than “boosted” 

reactions. 

Slide 36: Two-Step Testing – 1 

A strategy to determine the difference between boosted reactions and reactions due to recent infection. 

If 1st test positive, consider infected; if negative, give 2nd test 1–3 weeks later 

If 2nd test positive, consider infected; if negative, consider uninfected 

Use two-step tests for initial baseline skin testing of adults who will be retested periodically (e.g., health 

care workers). 
Slide 37: Two-step TST Testing – 2

This is a diagram describing two-step TST testing. Administer a baseline skin test. If the reaction is 

positive, the person probably has TB infection; provide follow-up for positive TST and evaluate for 

LTBI treatment. If the reaction is negative, retest 1 to 3 weeks later. If the reaction to the second test is 

positive, it is considered a boosted reaction (due to TB infection that occurred a long time ago). Note: 

The person does have LTBI; a decision must be made whether to treat or not. Provide follow-up for 

positive TST and evaluate for LTBI treatment. If the reaction to the second test is negative, the person 

probably does not have TB infection. Repeat TST at regular intervals; a positive reaction could be due to 

a recent TB infection. 

Slide 38: Interferon-Gamma Release Assays (IGRAs) 

Slide 39: Interferon-Gamma Release Assays (IGRAs) 

Whole-blood test used to detect M. tuberculosis infection 

Two U.S. Food and Drug Administration (FDA) approved IGRAs are commercially available in the 

U.S.:

QuantiFERON® -TB Gold-in-tube test (QFT-GIT) 

T.SPOT®.TB test (T-Spot)

[Image: photo of QuantiFERON-TB Gold In-Tube test kit] 

[Image: photo of T-Spot.TB test kit] 

Slide 40: How IGRAs Work – 1

Blood test that measures and compares amount of interferon-gamma (IFN-g) released by blood cells in 

response to antigens 

Entails mixing blood samples with antigens from M. tuberculosis and controls 

Slide 41: How IGRAs Work – 2

Cells that recognize the antigen release interferon-g

Amount of interferon released in response to M. tuberculosis antigens is compared to amount released in 

response to other antigens 

Slide 42: Administering IGRAs 

Confirm and arrange for delivery of blood sample within specific time-frame to ensure viability of blood 

samples 

Draw blood sample according to test manufacturer’s instructions
Schedule a follow up appointment to receive test results, medical evaluation and possible treatment if 

needed 

Slide 43: Interpretation of IGRA Test Results 

QFT-GIT test results are reported as positive, negative, indeterminate 

T-Spot test results are reported as positive, negative, indeterminate, or borderline

Note: Laboratory should provide both quantitative and qualitative results 

Slide 44: Advantages of IGRAs 

Requires a single patient visit to conduct test 

Results can be available within 24 hours 

Does not boost responses measured by subsequent tests 

Prior BCG vaccination does not cause false-positive IGRA test result 

Slide 45: Disadvantages/Limitations of IGRAs – 1

Errors in collecting and transporting blood, or in interpreting assays can decrease accuracy of IGRAs 

Limited data on use of IGRAs to predict who will progress to TB disease in the future 

Slide 46: Disadvantages/Limitations of IGRAs – 2

Tests may be expensive 

Limited data on the use of IGRAS for 

Children < 5 years of age; 

Persons recently exposed to M. tuberculosis; 

Immunocompromised persons; and 

Serial testing 

Slide 47: TB Test Selection 

Slide 48: Selecting a Test to Detect TB Infection – 1

IGRAs are preferred method of testing for 

Groups of people who have poor rates of returning to have TST read 

Persons who have received BCG vaccine 

TST is the preferred method of testing for 
Children under the age of 5 

Slide 49: Selecting a Test to Detect TB Infection – 2 

Before initiating treatment for LTBI 

Either TST or IGRA can be used without preference for other groups that are tested for LTBI 

Routine testing with TST and IGRA is NOT recommended 

Slide 50: Evaluation of Persons with Positive TB Test Results 

Slide 51: Evaluation of Persons with Positive TB Test Results 

This is a diagram explaining the evaluation of persons with positive TB test results. If a person has a 

positive test result for TB infection and TB disease is ruled out, consider the person for treatment of 

LTBI. If the person accepts and is able to receive treatment for LTBI, the clinician should develop a plan 

of treatment with the patient to ensure the patient’s adherence. But if the person refuses or is unable to 

receive treatment for LTBI, then follow-up TSTs or IGRAs and serial chest radiographs are 

unnecessary; in that case, the clinician would educate the patient about the signs and symptoms of TB 

disease. 

Slide 52: LTBI Treatment regimens 

Slide 53: Initiating Treatment 

Before initiating treatment for LTBI 

Rule out TB disease by history, physical examination, chest radiography and, when indicated, 

bacteriologic studies 

Determine prior history of treatment for LTBI or TB disease 

Assess risks and benefits of treatment 

Determine current and previous drug therapy 

Slide 54: Treatment Regimens for Latent TB Infection 

Drug(s) Duration Interval Minimum Doses

Isoniazid (INH) 9 months Daily 270

Twice weekly 76

6 months Daily 180

Twice weekly 52
Isoniazid (INH)and Rifapentine (RPT) 3 months Once weekly 12

Rifampin (RIF) 4 months Daily 120

Note: Rifampin (RIF) and Pyrazinamide (PZA) should not be offered to persons with LTBI. RIF and 

PZA should continue to be administered in multidrug regimens for the treatment of persons with TB 

disease. 

Slide 55: Latent TB Infection Treatment Regimens – Isoniazid (INH) – 1

9-month regimen of isoniazid (INH) is one of the preferred regimens

6-month regimen is less effective but may be used if unable to complete 9 months

May be given daily or intermittently (twice weekly) 

Use directly observed therapy (DOT) for intermittent regimen 

Preferred regimen for children 2-11 years of age 

Slide 56: Latent TB Infection Treatment Regimens – Isoniazid (INH) – 2

Doses 

INH daily for 9 months - 270 doses within 12 months 

INH twice/week for 9 months - 76 doses within 12 months 

INH daily for 6 months - 180 doses within 9 months 

INH twice/week for 6 months - 52 doses within 9 months 

Slide 57: Latent TB Infection Treatment Regimens – Isoniazid (INH) and Rifapentine (RPT) – 1

3-month regimen of INH and RPT is an option equal to 9-month INH regimen for treating LTBI in

certain groups, such as otherwise healthy people, 12 years of age and older, who were recently in contact

with infectious TB or who had tuberculin skin test conversions or positive blood test for TB*

Must use directly observed therapy (DOT) 

*Recommendations for Use of an Isoniazid–Rifapentine Regimen with Direct Observation to Treat

Latent Mycobacterium tuberculosis Infection

Slide 58: Latent TB Infection Treatment Regimens – Isoniazid (INH) and Rifapentine (RPT) – 2

Not recommended for children younger than 12 years of age, HIV-infected people taking antiretroviral 

therapy, pregnant women, or women expecting to be pregnant within the 12-week regimen 

INH and RPT once a week for 3 months - 12 doses within 4 months 
Slide 59: Latent TB Infection Treatment Regimens – Rifampin 

Rifampin (RIF) given daily for 4 months is an acceptable alternative when treatment with INH is not 

feasible. 

In situations where RIF cannot be used (e.g., HIV-infected persons receiving protease inhibitors), 

rifabutin may be substituted. 

RIF daily for 4 months - 120 doses within 6 months 

Slide 60: Latent TB Infection Treatment Regimens for Specific Situations – HIV-Infected Persons 

HIV-Infected Persons 

Consult an expert in managing HIV and TB 

INH daily for 9-mo, rather than 6-mo, is optimal: 270 doses within 12 months 

RIF is generally contraindicated for persons taking protease inhibitors or delavirdine 

Rifabutin with dose adjustments can sometimes be substituted for RIF 

INH/RPT regimen not recommended for HIV-infected people taking antiretroviral therapy 

Slide 61: Latent TB Infection Treatment Regimens for Specific Situations – Fibrotic Lesions 

Persons with Fibrotic Lesions Suggesting Previous TB 

Should be treated for LTBI if they have 

A positive TST reaction (at least 5 mm) or IGRA result 

No symptoms of infectious TB disease 

No history of treatment for TB disease 

Treat only after active disease excluded with sputum testing 

Acceptable regimens include 

9 months of INH 

4 months of RIF (with or without INH) 

3 months of INH and RPT (12-dose regimen) 

Slide 62: Latent TB Infection Treatment Regimens for Specific Situations – Multidrug-Resistant 

TB

Contacts of Persons with Multidrug-Resistant TB 

Consider risk for progressing to MDR disease before recommending LTBI treatment 
When prescribing treatment for these contacts, consult an MDR TB expert 

Slide 63: Latent TB Infection Treatment Regimens for Specific Situations - Pregnancy 

Pregnancy and Breast-Feeding 

9 months of INH daily or twice weekly; give with vitamin B6 

If cannot take INH, consult with TB expert 

Women at high risk for progression to TB disease should not delay LTBI treatment; monitor carefully 

Breast-feeding not contraindicated 

Slide 64: Completion of Therapy 

Completion of therapy is based on the total number of doses administered, not on duration alone. 

Slide 65: Management of Patient Who Missed Doses 

Extend or re-start treatment if interruptions were frequent or prolonged enough to preclude completion 

When treatment has been interrupted for more than 2 months, patient should be examined to rule out TB 

disease 

Recommend and arrange for DOT as needed 

Slide 66: Monitoring Drug Treatment 

Slide 67: Clinical Monitoring – 1

Instruct patient to report signs and symptoms of adverse drug reactions: 

Fever

Headache 

Rash 

Anorexia, nausea, vomiting, or abdominal pain in right upper quadrant 

Fatigue or weakness 

Dark urine 

Persistent numbness in hands or feet 

Slide 68: Clinical Monitoring – 2

Monthly visits should include a brief physical exam and a review of: 

Rationale for treatment 
Adherence with therapy 

Symptoms of adverse drug reactions 

Plans to continue treatment 

Slide 69: Clinical Monitoring – 3

Incidence of hepatitis in persons taking INH is lower than previously thought (as low as 0.1%) 

Hepatitis risk increases with age 

Uncommon in persons < 20 years old 

Nearly 2% in persons 50 to 64 years old 

Risk increases with underlying liver disease or heavy alcohol consumption 

Slide 70: Laboratory Monitoring – 1

Baseline liver function tests (e.g., AST, ALT, and bilirubin) are not necessary except for patients with 

risk factors: 

HIV infection 

History of liver disease 

Regular alcohol use 

Pregnancy or in early postpartum period 

Slide 71: Laboratory Monitoring – 2

Repeat laboratory monitoring if patient has: 

Abnormal baseline results 

Current or recent pregnancy 

High risk for adverse reactions 

Symptoms of adverse reaction 

Liver enlargement or tenderness during examination

Slide 72: Laboratory Monitoring – 3

Asymptomatic elevation of hepatic enzymes seen in 10%-20% of people taking INH 

Levels usually return to normal after completion of therapy 
Discontinue treatment if transminase level exceeds 3 times the upper limit of normal if patient has 

symptoms of hepatoxicity, and 5 times the upper limit of normal if patient is asymptomatic 

Slide 73: Meeting the Challenge of TB Prevention 

For every patient: 

Assess TB risk factors 

If risk is present, perform TST or IGRA 

If TST or IGRA is positive, rule out TB disease 

If TB disease is ruled out, initiate treatment for LTBI 

If treatment is initiated, ensure completion 

Slide 74: Additional Resources 

Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection. MMWR 2000; 49 (No.

RR-6)(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/rr4906a1.htm)

Recommendations for Use of an Isoniazid–Rifapentine Regimen with Direct Observation to Treat Latent 

Mycobacterium tuberculosis 

Infection(http://wwwdev.cdc.gov/mmwr/preview/mmwrhtml/mm6048a3.htm?s_cid=mm6048a3_w) 

CDC TB Website(http://wwwdev.cdc.gov/tb/default.htm) 

Latent Tuberculosis Infection: A Guide for Primary Health Care Providers 

Slide 75: Additional TB Guidelines Available Online 

CDC’s Morbidity and Mortality Weekly Report

http://www.cdc.gov/tb/publications/reportsarticles/mmwr/default.htm 

American Thoracic Society 

http://www.thoracic.org/statements/ 

U.S. Preventive Services Task Force

http://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryDraft/latenttuberculosis-infection-screening

Bright Futures Recommendations for Pediatric Preventive Health Care

https://www.aap.org/en-us/Documents/periodicity_schedule.pdf

Slide 76: Case Studies 

Slide 77: Case Study A (1) 

Patient History 
No symptoms of TB disease 

Normal CXR, CBC, AST, and bilirubin 

Slide 78: Case Study A (2) 

Questions 

What are this patient’s risk factors for TB infection or disease?

Has the management of this patient to date been appropriate? 

Slide 79: Case Study A (3) 

Discussion of risk factors 

Patient is a contact of an infectious TB case 

Recent immigrant to the US from a country with a high prevalence of TB 

If the patient had not been a contact, the recency of his immigration (less than 5 years) would have made 

him a candidate for TB testing, but the 5-mm reaction would not be considered positive 

Slide 80: Case Study A (4) 

Discussion of risk factors 

Persons who immigrate from TB-endemic countries have increased rates of TB 

Rates of TB approach those of their countries of origin for 5 years after arrival in the U.S. 

These increased rates most likely result from recent M. tuberculosis infection in their native country 

Slide 81: Case Study A (5) 

Discussion of management 

As a contact of an active TB case, 5 mm of induration is considered positive 

This patient should have been treated for LTBI immediately after the first TST 

Slide 82: Case Study B (1) 

Patient History 

24-year-old Asian female

Moved to U.S. from Philippines > 5 years ago 

Plans to work in a correctional facility 
TST result negative (0 mm) 1 year ago 

TST for pre-employment physical = 26 mm of induration 

CXR normal 

No symptoms of TB disease 

No known contact with a TB patient 

Slide 83: Case Study B (2) 

Questions 

What are this patient’s risk factors for TB infection or disease?

What is the appropriate management for this patient? 

Slide 84: Case Study B (3) 

Discussion of risk factors 

Patient’s TST converted from negative to positive (within a 2-year period) 

TST conversion increases risk for progressing from LTBI to TB disease 

Foreign-born status is less of a risk factor, i.e., she immigrated more than 5 years ago 

Slide 85: Case Study B (4) 

Discussion of management 

Patient’s TST conversion indicates failure to identify this person as high risk for recent exposure to TB 

Patient may have had extended travel to her country of origin or other high-prevalence parts of the world 

Patient is a recent converter and, as such, is a candidate for treatment of LTBI with INH 

Slide 86: Case Study C (1) 

Patient History 

28-year-old Asian male

Moved to U.S. from China < 5 years ago 

Received BCG vaccine in China as a child 

QFT-GIT result = Positive 

CXR normal 
No symptoms of TB disease 

Known contact with a TB patient 

Slide 87: Case Study C (2) 

Questions 

What are this patient’s risk factors for TB infection or disease?

What is the appropriate management for this patient? 

Slide 88: Case Study C (3) 

Discussion of risk factors 

Positive QFT-GIT result suggests that M. tuberculosis infection is likely (result is not affected by prior 

BCG vaccination) 

Recent immigrant to the US from a country with a high prevalence of TB 

Foreign-born status is a risk factor, i.e., he immigrated < 5 years ago 

Known contact with a TB patient 

Slide 89: Case Study C (4) 

Discussion of management 

Patient recently immigrated from a TB endemic country, positive QFT-GIT result may be indicative of 

LTBI 

Contact with a TB patient could have been source of infection 

Should be treated for LTBI