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Am Fam Physician. 2003 Apr 1;67(7):1625-1626.

CDC Guidelines for QuantiFERON-TB Test

The Centers for Disease Control and Prevention (CDC) has issued recommendations on using the Quanti-FERON-TB (QFT) test for diagnosing latent tuberculosis infection (LTBI). The recommendations are available online at www.cdc.gov/mmwr/preview/mmwrhtml/rr5202a2.htm.

QFT was approved by the U.S. Food and Drug Administration in 2001 as an aid for detecting latent Mycobacterium tuberculosis infection. The in vitro test measures a component of cell-mediated immune reactivity to M. tuberculosis. QFT requires phlebotomy, can be accomplished after a single patient visit, simultaneously assesses response to multiple antigens, and does not boost anamnestic responses. Limitations include the need to draw blood and process it within 12 hours. Compared with tuberculin skin testing, QFT results are less subject to reader bias and error.

The highest priority of targeted tuberculin testing programs is identifying persons at increased risk for tuberculosis who will benefit from treatment for LTBI. Targeted testing should be conducted among groups at risk for recent infection with M. tuberculosis and persons who, regardless of duration of infection, are at increased risk of progression to active tuberculosis.

According to the guidelines, QFT can be considered for serial and initial testing of persons with an increased risk for LTBI (e.g., recent immigrants, injection drug users, residents and employees of prisons or jails) and of persons who are at low risk for LTBI but whose future activities might put them at increased risk for exposure (e.g., health care workers, military personnel). QFT also can be considered for testing of persons for whom LTBI testing is performed but who are not at increased risk for infection (e.g., as an entrance requirement for school or work).

Before QFT testing is considered, the CDC recommends making arrangements with a qualified laboratory that will assure quality of testing and collection, and transport of blood within the required 12 hours.

Confirmation of QFT results with tuberculin skin testing is possible; the probability of LTBI is greatest when results from both tests are positive. To confirm a positive test, the CDC recommends the following:

  • When the probability of LTBI is low, confirmation of a positive QFT result with tuberculin skin testing is recommended before initiating treatment. Therapy is not recommended for persons at low risk who are QFT-negative or who are QFT-positive but negative with tuberculin skin testing.

  • Tuberculin skin testing can be used to confirm a positive QFT for persons at increased risk for LTBI. However, the need for treatment when QFT is positive and the subsequent tuberculin skin testing is negative should be based on clinical judgment and perceived risk.

  • Negative QFT results do not require confirmation, but results can be confirmed with either a repeat QFT or tuberculin skin testing if accuracy of the initial test is in question.

Because of insufficient data on which to base recommendations, the CDC does not recommend QFT in the following situations:

  • Evaluation of persons with suspected tuberculosis infection. Active tuberculosis infection is associated with suppressed interferon-gamma responses, and in prior studies, fewer persons with active tuberculosis infection had positive results with QFT than with tuberculin skin testing. The degree of suppression appears to be related to the severity of disease and the duration of therapy.

  • Assessment of contacts of persons with infectious tuberculosis. Rates of conversion of QFT and tuberculin skin testing after a known exposure to M. tuberculosis have not been compared.

  • Screening of children younger than age 17, pregnant women, or persons with clinical considerations that increase the risk of progression of latent infection to active infection (e.g., persons with human immunodeficiency virus infection).

  • Detection of LTBI after suspected exposure of persons participating in longitudinal LTBI surveillance programs.

  • Confirmation of tuberculin skin testing results. Injection of purified protein derivative for tuberculin skin testing might affect subsequent QFT results. Although QFT is not recommended for confirmation of tuberculin skin testing results, it can be used for surveillance 12 months after a negative tuberculin skin test, if the initial QFT is negative.

  • Diagnosis of Mycobacterium avium complex disease.

NIH Launches HIV/AIDS Web Site

The National Institutes of Health (NIH) has launched AIDSinfo, a new Web site offering information on human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) for health care professionals, researchers, persons with HIV/AIDS, and the general public. The Web site, aidsinfo.nih.gov, combines two information services (the HIV/AIDS Treatment Information Service [ATIS] and the AIDS Clinical Trials Information Service [ACTIS]) into one searchable resource.

The new Web site contains treatment guidelines, information on approved therapies for HIV/AIDS, an HIV glossary, information on federally funded and privately sponsored clinical trials, and information on vaccines.

AIDSinfo also features a telephone service. Trained specialists who speak English and Spanish are available to talk with persons who may not have access to the Web. The telephone number is 800–448–0440.

AHRQ Launches Web-Based Quality Measures Resource

The Agency for Healthcare Research and Quality (AHRQ) has launched its Web-based National Quality Measures Clearinghouse, which will contain the most current evidence-based quality measures and measure sets to evaluate and improve the quality of heath care. The resource is available online at www.qualitymeasures.ahrq.gov.

Physicians, hospital staff, health plan employees, and others interested in quality measures can search the site for measures that target a particular disease or condition, treatment or intervention, age range, gender, vulnerable population, setting of care, or contributing organization. Users also can compare attributes of two or more quality measures side by side to determine which measures best suit their needs. The site also provides material on how to select, use, apply, and interpret a measure.

The new site builds on AHRQ's previous initiatives in quality measures and will be part of a larger Web site of quality, clinical information, and decision tool components that will include the National Guideline Clearinghouse (www.guideline.gov).

FDA Approval

Finacea. The U.S. Food and Drug Administration (FDA) has approved azelaic acid gel 15 percent (Finacea Gel) for the topical treatment of the inflammatory papules and pustules associated with mild to moderate rosacea.

Azelaic acid gel is the first new drug to be approved for treatment of rosacea in more than a decade. The exact mechanism of the drug is unclear, but clinical tests have shown that the drug interferes with the pathogenic events in rosacea. Treatment effects were reported after four weeks of therapy.

In clinical trials, the most frequently reported adverse effects related to azelaic acid gel included burning, tingling, and itching. Up to 10 percent of patients experienced dry skin and rash, the majority of which were mild.



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