County of San Francisco First in Country to Diagnose Tuberculosis Infection With QuantiFERON-TB GOLD

VALENCIA, Calif. -- As part of its steadfast effort to control the spread of tuberculosis (TB), the San Francisco Health Department today became the first county health department in the U.S. to use QuantiFERON-TB GOLD, an indirect test for TB infection.  This follows closely on the heels of Medi-Cal reimbursement for the modern alternative to the 115-year-old tuberculin skin test (TST), which despite its widespread use

is notoriously unreliable due to false-positive and false-negative results.


Approved by the FDA in December 2004, QuantiFERON-TB GOLD is a simple,

one-step blood test that detects immune responses to specific proteins

associated with infection by Mycobacteria Tuberculosis.  By finally providing

clinicians with an accurate, reliable and convenient TB diagnostic tool, the

breakthrough test is well positioned to become the new gold standard for TB

screening and control.


While the overall TB incidence in the U.S. is slowly decreasing, TB is

resurfacing in several "hot spot" metropolitan areas, such as San Francisco,

where 231 active TB cases were reported to the CDC in 2003 (13.6 per 100,000).

As an international city with large immigrant and migrant populations, as well

as a high number of individuals with immunosuppressive diseases such as

HIV/AIDS, the San Francisco metropolitan area has one of the highest TB rates

in the U.S.  An untold number of individuals are infected with TB in its

dormant, or latent, phase and are at risk of developing active TB disease and

becoming highly contagious.  Therefore, the accurate identification of people

with latent TB infection is important in the prevention of further spread of

the disease.


"Medi-Cal reimbursement of QuantiFERON-TB GOLD is a tremendous achievement

because it opens the door for wider adoption in California, a state with

several TB 'hot spots,'" said Tony Radford, PhD, CEO of Cellestis.  "The

urgent need for a new tool to more accurately identify individuals who are

infected and those who are at risk of developing tuberculosis has been

reinforced by a state that is a bellwether for the rest of the country."


QuantiFERON-TB GOLD is an in vitro diagnostic test unaffected by

subjective interpretation, previous TB vaccination and cross-reactivity with

most non-tuberculous or environmental mycobacteria.  This means virtual

elimination of TST false-positive individuals normally recommended for

unnecessary and potentially harmful TB therapy.  False-positive rates can be

as high as 50 percent of all TST responses (von Reyn et al. Int J. Tuberc

Lung Dis 5(12), 2001).


When compared with the TST, QuantiFERON-TB GOLD has been demonstrated to

yield dramatic cost savings in terms of medical staff time and the elimination

of common false-positive results.  According to a recent study (Lambert et al.

Infection Control and Hospital Epidemiology Nov. 2003), researchers found that

the cost of running a TB control program using the TST is considerably more

expensive than the simple cost of the supplies, given the labor required to

successfully perform the TST.  Specifically, costs to a hospital ranged from

$41 to $362 per employee, with the TST supplies representing less than

1.5 percent of the total cost of the program.


"After FDA approval, the California TB Controllers Association began

aggressively making the case to Medi-Cal for reimbursement of QuantiFERON-TB

GOLD, realizing the importance of this new technology," said Dr. Masae

Kawamura, TB controller for the city of San Francisco.  "With large numbers of

immigrants and high risk patients served by San Francisco's county health

department, a more accurate test for TB has long been awaited.  Now that

Medi-Cal has approved payment of QuantiFERON-TB GOLD, San Francisco has a real

chance of providing the public with a safer and more accurate test, without

breaking the bank.  QuantiFERON-TB GOLD will eliminate the waste of precious

health resources from inaccurate skin tests and improve public safety by

preventing unnecessary treatment."


The National TB Controllers Association strongly advocates the use of

FDA-approved blood test to diagnose latent TB infection


Further support for QuantiFERON-TB GOLD was provided by the National TB

Controllers Association (NTCA) with the issue of their official position

statement (January 2005), advocating the use of FDA approved in vitro

diagnostic tests for diagnosis of latent TB infection.  QuantiFERON-TB Gold is

currently the only such test.  The NTCA states that "...the TST has many

limitations and that a new test to replace the TST has been sought for many

years."  The NTCA recognizes that various problems with the TST, including

operational limitations, subjective interpretation, false positive and false

negative results "...make the TST a frustrating test for patients and

providers and have led to recommendations that are often poorly followed,

accepted, or understood."  The NTCA believes that "...blood assays done in

vitro are likely to become the test of choice for most or all populations in

the future."


Source: Cellestis