Tuberculosis Screening and Treatment (TB TIs) using Cultures and Directly Observed Therapy (DOT) Frequently Asked Questions (FAQ)
What are the tuberculosis (TB) Technical Instructions?
HHS/CDC regulations require that all immigrants and refugees coming to the United States be screened for tuberculosis (TB). CDC’s Division of Global Migration and Quarantine (DGMQ) develops physician guidelines for TB testing and treatment of immigrants and refugees that are called Technical Instructions.
Why are there different sets of TB Technical Instructions?
The original TB Technical Instructions developed in 1991 were based on the best screening tests and treatment known at that time. The TB Technical Instructions were updated in 2007 to use newer, more precise tests to reduce the chance of bringing TB into the United States and improve the health of immigrants and refugees through earlier diagnosis and updated methods of treatment.
How are the TB TIs using Cultures and Directly Observed Therapy (DOT) being implemented?
CDC is working to apply the TB TIs using Cultures and Directly Observed Therapy (DOT) to all countries and implements them according to a number of factors. The guidelines are being implemented in a few countries each year. The order of implementation is based on a country’s number of immigrants coming to the United States, the number of refugees resettling to the United States, the health care resources in the country, the rates of TB in the country, and the rate of TB in immigrant groups in the United States.
How do the 1991 TB Technical Instructions screen for TB?
The 1991 TB Technical Instructions call for a chest x-ray and three sputum samples (i.e., a small amount of mucus from deep in the lungs) to determine if immigrants or refugees have TB. The sputum sample is looked at by a lab to see if TB bacteria are present.
What was updated in the TB TIs using Cultures and Directly Observed Therapy (DOT)?
CDC updated the TB guidelines in 2007 to make testing more precise by requiring cultures for immigrant applicants and refugees thought to have TB. A culture test involves putting a sputum sample (i.e., a small amount of mucus from deep in the lungs) in a petri dish to see if TB bacteria grow. Drug susceptibility testing (DST) on positive TB cultures was added to see which drugs would be likely to kill the type of TB found.
Another update is the addition of directly observed therapy (DOT). Treatment must start before arrival in the United States and medical staff must observe patients in person as they swallow each dose of TB drug.
How do the TB TIs using Cultures and Directly Observed Therapy (DOT) affect the TB evaluation in children?
To help detect TB in children, the TB TIs using Cultures and Directly Observed Therapy (DOT) require that children aged 2 through 14 years undergo a TB skin test if they are medically screened in countries where the TB rate is 20 cases or more per 100,000 population. If the skin test is positive, a chest X-ray is required. If the chest X-ray suggests TB, cultures and three sputum smears are required.
For a sputum smear, a small amount of mucus is collected from deep in the lungs (sputum), smeared on a slide, and viewed under a microscope to look for TB bacteria. A culture involves putting a sputum sample (i.e., a small amount of mucus from deep in the lungs) in a petri dish to see if TB bacteria grows.
Do the requirements of the TB Technical Instructions apply to children from other countries who are being adopted by U.S. citizens?
Yes. The TB Technical Instructions apply to immigrant medical screening. Children from other countries who are being adopted by U.S. citizens are applying for U.S. entry as immigrants. They, therefore, must undergo the required immigrant TB examination, according to CDC’s Technical Instructions.
How has CDC revised the tuberculosis (TB) Technical Instructions for children age 10 and younger?
Now children aged 10 and younger with a positive TB skin test can travel as long as other TB tests do not suggest that they are likely to spread the disease to others.
All immigrants and refugees applying for a U.S. immigrant visa must complete a medical exam. This exam includes screening for TB. If an applicant has a positive TB skin test, a chest x-ray and three sputum samples are taken to do further testing. Sputum samples are used in smear and culture tests, which are very useful in detecting TB. Although, smear tests can be done quickly, cultures take 6-8 weeks before results are final.
Immigrant applicants over age 10 cannot travel to the United States until these culture results are ready. But, for children age 10 and younger, the process is now slightly different. Typically, young children are not infectious (able to spread TB). However, even in young children, if certain factors are present care should be taken to decrease the risk of spreading TB to others. Therefore, children age 10 and younger must wait until culture results are ready if they have any of the following:
- Positive sputum smears
- A chest x-ray that shows
- One or more cavities, or
- Widespread TB disease in the lungs (especially in the upper area of the lungs)
- A forceful and productive cough
- Contact with a person who has multidrug-resistant tuberculosis (MDR TB) who could have spread TB at the time of contact
Sometimes children cannot provide sputum samples. In these cases, a special procedure is done to collect fluid from the stomach for smear and culture tests. This procedure is known as gastric aspiration. Children age 10 and younger who have positive smears after this procedure can still travel to the United States before cultures are ready.
Why do these instructions only apply only to children age 10 and younger?
It is rare that children age 10 and younger can spread TB to others. Children over age 10 are more likely to have TB that can be easily spread to others.
Since children age 10 and younger are less likely to spread TB to others, they do not pose a major public health risk. Thus, CDC will now allow immigrant applicants in this young age group to travel to the United States after sputum has been collected, if they do not show signs that they are infectious (or, that they can spread TB to others).
What does the term “cavities” refer to in the Technical Instructions?
Cavities are hollow spaces within the lungs that may contain TB bacteria. They can be seen on a chest x-ray and are often found in people with severe TB disease. These people are typically very infectious (meaning that they are able to spread TB to others).
If an immigrant applicant age 10 or younger is found to have cavities in the lungs, he or she is likely infectious. Thus, the child must wait for the medical screening to be complete before the immigration process can be completed. This includes waiting for sputum culture results, which take 6-8 weeks.
How does CDC know if a child age 10 and younger has a “forceful and productive cough?”
During the medical exam, a panel physician will check a patient’s health in a number of ways. If a patient is coughing, a panel physician will determine if that cough is forceful and productive. Children who have a forceful or productive cough are better able spread TB to others through their coughing.
Patients who have a positive skin test, a chest x-ray that shows signs of TB, and a cough that is forceful and productive may have more severe TB disease. Thus, any immigrant applicant with these signs and symptoms must wait until cultures are complete before traveling to the United States or receiving a U.S. immigrant visa. The culture process takes 6-8 weeks.
If the results from cultures are ready before a child (age 10 and younger) leaves for the United States, can the child still leave?
If cultures come back negative, the child may leave for the United States.
If cultures comes back positive before a child leaves for the United States, the child needs to begin TB treatment in the country of origin. However, a waiver can be filed through the U.S. consulate for a child with positive cultures. If the waiver request is granted by the U.S. Department of Homeland Security, the child may be able to travel to the United States before treatment is finished.
For more information on the waiver process, please see: DHS Waiver Information.