The Center for Disease ascendency a...

The Center for Disease ascendency and Prevention (CDC) has issued recommendations in succession using the QuantiFERON-TB (QFT) criterion for diagnosing latent tuberculosis infection (LTBI). The recommendations are available online at wwwcdcgov/ mmwr/preview/mmwrhtml/rr5202a2.htm.

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

The highest priority of targeted tuberculin testing programs is identifying human frames at increased risk for tuberculosis who will benefit from treatment for LTBI. Targeted testing should be leadershiped among groups at risk for novel infection with M. tuberculosis and human frames 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 parts with an increased risk for LTBI (eg modern immigrants, injection drug users, residents and employee of prisons or jails) and of living bodys who are at low risk for LTBI yet whose future activities might enjoin them at increased risk for in all senses (e.g., health care workers, military personnel) QFT also can be considered for testing of ones for whom LTBI testing is performed however who are not at increased risk for infection (eg as an entrance requirement for sect or work).

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

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

* When the probability of LTBI is soft confirmation of a positive QFT proceed with tuberculin skin testing is commended before initiating treatment. Therapy is not attract favor toed for persons at low risk who are QFT-negative or who are QFT-positive if it were not that negative with tuberculin skin testing.

* Tuberculin skin testing can be used to confirm a positive QFT for bodily substances at increased risk for LTBI. However, the ne for treatment when QFT is positive and the posterior tuberculin skin testing is negative should be based forward clinical judgment and perceived risk.

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

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

* Evaluation of ones with suspected tuberculosis infection. Active tuberculosis infection is associated with put downed interferon-gamma responses, and in prior studies, fewer someones with active tuberculosis infection had positive terminates with QFT than with tuberculin skin testing. The stage of suppression appears to be related to the severity of disease and the duration of therapy.

* Assessment of contacts of somebodys with infectious tuberculosis. Rates of conversion of QFT and tuberculin skin testing after a known aspect to M. tuberculosis have not been compared.

* Screening of children younger than age 17 pregnant women or bodys with clinical considerations that increase the risk of progression of latent infection to active infection (eg human frames with human immunodeficiency virus infection).

* Detection of LTBI after suspected prospect of persons participating in longitudinal LTBI surveillance programs.

* Confirmation of tuberculin skin testing accrues Injection of purified protein derivative for tuberculin skin testing might affect following QFT results. Although QFT is not commended for confirmation of tuberculin skin testing ensues it can be used for surveillance 12 month after a negative tuberculin skin exhibition if the initial QFT is negative.

* Diagnosis of Mycobacterium avium manifold disease.

COPYRIGHT 2003 American Academy of Family Physicians

COPYRIGHT 2003 Gale Group