Review of PPDs

We have a lot to learn regarding TB, but regarding the targeted testing for latent tuberculosis infection, here is a VERY QUICK review of what constitues a positive PPD:

>0 mm is considered a positive reaction if the patient:

• Is HIV-positive or immunocompromised AND are recent contacts to known or suspected infectious TB disease, regardless of previous treatment of LTBI
• Is HIV-positive with fibrotic changes on CXR consistent with prior TB who have received inadequate or no treatment for TB disease
• Is a child <5>

>5 mm is considered a positive reaction if the patient:

• Is HIV-positive
• Is a contact to known or suspected infectious TB case identified within the last two years
• Has fibrotic changes on CXR consistent with prior TB and have received inadequate or no treatment for TB disease
• Is Immunocompromised (receiving >15mg per day of Prednisone for one month, other immunosuppressive drugs, organ transplant recipients, persons taking TNF inhibitors)

>10 mm is considered a positive reaction if the patient:

• Is foreign-born from Asia, Africa, Carribean, Latin America, Mexico, South America, Pacific Islands, or Eastern Europe)
• Has converted their TST within two years
• Has a medical condition placing them at high-risk for TB Disease (DM, CRI, Chronic malabsorption syndrome, Leukemias and Lymphomas, Cancer of the head and neck, Silicosis, Weight loss of >10% ideal body weight, gastrectomy or intestinal bypass)
• Is an injection drug or crack cocaine user
• Is a child <4>
• Works in a mycobacterial lab

*Also, this cutoff is used per the clinicians judgement for: residents of long-term care facilities and homeless shelters, are inmates in the DOC, OR are employees in prisons/jails, long-term care facilities, hospitals/health care facilities, adult day-care centers for HIV patients, homeless shelters).

>15 mm is considered a positive reaction if the patient:

• Has NO risk factors for TB

Hope this helps!

Yvonne Carter, MD

Working with the Health Department regarding Tuberculosis Management

North Carolina Health Departments are a vital resource for TB evaluation and management. In most cases, Tuberculosis evaluation can be done as an outpatient, and does not require inpatient admission and evaluation, or ID clinic follow up. Each Health Department houses a TB Clinic, whose responsibilities include:

• providing case management to all active cases of TB,


• evaluating all persons suspected of having TB,


• evaluating all contacts of active and suspect cases within the county, and


• providing TB screening to predetermined high-risk individuals, including recent immigrants.

Evaluation, treatment, and care is provided to each patient free of charge. It is important to note that patients can be referred to the Health Department during any part of the workup for TB, from suspicion through post-diagnosis care. If a patient is hospitalized at UNC, and is on isolation for suspicion of TB, and is otherwise ready for discharge, they may be discharged with a mask to follow up with the Health Department. The Health Department, however, MUST be notified of the patient's discharge, and set up an appointment for the patient to be seen by them. There, they can complete sputum collection, PPD placement and reading, and contact investigation. Again, the pt must present to the Health Department with a mask if TB is suspected. If a patient is suspected of having Tuberculosis, but refuses follow-up with the Health Department, that patient's workup should be done as an inpatient.

If a patient has a positive sputum AFB smear, and treatment is initiated, you will need to give the patient enough doses to last them until they can be seen at the Health Department (the next day if during the week, and on Monday if during the weekend). The Health Department will treat TB only, not infections caused by nontuberculous mycobacterium.

A directory of health departments for each county can be found at: http://www.ncalhd.org/county.htm.

Yvonne Carter, MD