Sample & Assay Technologies - 1 - For Internal Use Only Effectively screening for Latent TB HIV/STD/TB/Hepatitis Symposium North Dakota April 2012 . Mary Shragal Area Director Sales, Northern Region USA Cellestis, Inc. a Qiagen Company QuantiFERON ® -TB Gold In-Tube
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Effectively screening for Latent TB HIV/STD/TB/Hepatitis Symposium North Dakota April 2012 .
QuantiFERON ® -TB Gold In-Tube . Effectively screening for Latent TB HIV/STD/TB/Hepatitis Symposium North Dakota April 2012 . Mary Shragal Area Director Sales, Northern Region USA Cellestis, Inc. a Qiagen Compan y. A little history. • In the 1980’s the need for a better test for TB - PowerPoint PPT Presentation
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Sample & Assay Technologies- 1 -For Internal Use Only
Effectively screening for Latent TB
HIV/STD/TB/Hepatitis SymposiumNorth Dakota
April 2012
.
Mary ShragalArea Director Sales,
Northern Region USACellestis, Inc. a Qiagen Company
QuantiFERON®-TB Gold In-Tube
Sample & Assay Technologies- 2 -For Internal Use Only
A little history
•
In the 1980’s the need for a better test for TBinfection in cattle was addressed in Australia
• The tuberculin skin test in cattle had very similarproblems to the TST in humans and thus a new
test was neededI
But also was a very messy test to perform
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History of QuantiFERON®
1980’sDeveloped by Australian researchers at CSIRO for detecting TB in
Australian cattle herds
Early 1990’sCSL (Australia) acquired exclusive license to patents; and undertook
commercialization of a cattle diagnostic test and development of a human diagnostic for TB
2000Cellestis, founded by two of the inventors of the QuantiFERON®
technology, was chosen to commercialize the human TB diagnostic, known as QuantiFERON® -TB
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Developed in Cattle – An Excellent Model for Human TB
4
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Skin Testing Cows Australia 1990’s
Injecting tuberculin from M.bovis into the caudal fold
(base of tail) of a cow.
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Tuberculosis (TB) Review
Bacterial infection caused by Mycobacterium tuberculosis complex organismsM. tuberculosis, M. bovis, M. africanum
Infection may be eitherActive (with all symptoms and highly contagious)Latent (without any symptoms, not contagious)
Latent TB infection (LTBI)Needs treatmentProgression to active disease
Treatment involves 6-9 months antibiotic therapy; new therapy once per week for 12 weeks.
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LTBI Active TB
• LTBI means infection, no active disease, no symptoms, not contagious
• If undetected and untreated
10% will progress to disease
50% do so within 2 years
Higher for immuno-compromised individuals
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Active tuberculosis: Signs and symptoms
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Sample & Assay Technologies World Facts on TB
• At least one person becomes infected every second
• Each year, more than 9 million people develop TB disease
• The WHO estimates that TB takes a life every 17 sec
• Almost 2 million TB-related deaths occur each year
• TB is the leading killer of people who are HIV-infected
• Global mobility, immigration, and inadequate control strategies make it a worldwide problem
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Global travel makes it worse
Journal of the American Medical Association
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Transmission of TB
Family, friends, workmates etc.
exposed
Active TB:Infectious
Not infected
Infected, but no symptoms“Latent TB infection”
If not identified & treated ~10%
develop TB disease during their lifetime
If identified & treated they don't develop TB disease
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Conventional TB Diagnostics, desperately in need of an upgrade
Purified Protein Derivative (PPD) is injected intradermally
48 – 72 hours later the size of the resultant reaction is measured
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Tuberculin Skin Test (TST) Limitations:
TST responses are often not read within time window Poor compliance Cost implications (follow up and re-testing) Employee health implications
False positives due to BCG & NTM
Inaccuracy of measuring induration; Subjective interpretation 1 in 3 TST’s failed to be properly diagnosed (Kendig et.al. 1998)
2-step testing required for new hires Up to 4 consultations (usually 10 days)
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TB and the 21st Century
QuantiFERON®-TB Gold ‘‘In-tube’
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And counting…
1,100,000tests/year in the US
• Testing rate >3,000,000 per year and growing
• US rate >1,100,000 per year– Majority are serial screening of HCW’s– In Europe, mainly contacts, immunesuppressed,
TB suspects– In Asia, contacts, TB suspects, HCWs
• Worldwide > 1000 labs running QFT– In the US >300 routinely using QFT
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QuantiFERON®-TB Gold
Procedures & Guidance
• Blood Collection• Laboratory ELISA• Data Analysis
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In the field:• 3 tubes: TB specific
antigen, Nil & Mitogen
• Blood collected directly into tubes (1mL each)
In the lab:• ELISA for detection of
IFN-gamma
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Blood Collection
Set of three collection tubes: Nil, TB-Antigen, Mitogen• Draw 1 mL of blood into each of the 3 tubes• Black side marking on the tube indicates the 1mL fill line
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Shaking of Tubes
• Tubes are mixed by shaking for 5 seconds (~10x)• After shaking, the entire inner surface of each tube
should be coated with blood• Proper shaking will lead to some frothing of the blood
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After Blood Collection and Shaking
Tubes can be held at Room Temperature for up to 16 hours
Following incubation, tubes have up to 3 days for transfer to
lab for QFT ELISA
Within 16 hours of collection/shaking, tubes must be incubated at 37ºC for 16-24
hours
Option 1:
Option 2:
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Data Analysis and Results
Results are reported as: Positive Negative Indeterminate
Indeterminate Low mitogen High Nil
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Clinical performance of QuantiFERON ®-TB Gold
A sensitive test would accurately identify people with infection, whether latent or active (maximize true positive results)
A specific test would accurately identify people who are uninfected (maximize true negative results)
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Real World Experiences
NYC Dept. of Health
San Francisco Dept. of Health
University of Illinois Chicago
Cleveland Clinic
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2nd Global symposium on IGRA’s (Dubrovnik, Croatia, June 2009)
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Performance of IGRAs and the TST:An up-to-date TB Test Meta-Analysis
RDiel, R Loddenkemper and A NienhausEvidence based comparison of commercial interferon-gamma release assays for detecting active tuberculosis – a meta-analysis. Chest, 2009, Published on Dec 18, 2009 in electronic format;
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Key findings from meta-analysis:IGRA and TST specificity
*QFT significantly more specific than both the TST and T-Spot (p<0.0001)
p<0.0001
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Key findings: IGRA and TST Specificity
QFT In-Tube
T-Spot.TB TST0
100
200
300
400
500
8
137
410
Fal
se-P
ositi
ves/
1000
test
s
p<0.0001
How does this translate into false-positives per 1,000 tested people without TB?
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IGRA Indeterminate rates from Diel et al, Chest, 2009
QFT Number of subjects
Number Indeterminate
% indeterminate
Immune competent 16,449 227 1.38%
Immune suppressed 5,473 242 4.42%
T-Spot.TB
Immune competent 9,584 304 3.17%
Immune suppressed 2,581 158 6.12%
For both IGRAs there are significantly more indeterminate results in those immune suppressed
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Negative and positive predictive value of a whole-blood IGRA for developing active TB - an updateDiel R, Loddenkemper R, Niemann S, Meywald-Walter K, Nienhaus A
Am J Respir Crit Care Med 2010. [Epub Aug 27, 2010]
M31635074C
An analysis of 954 tuberculosis contacts comparing QuantiFERON® TB Gold (QFT®) and tuberculin skin test (TST)
Cellestis Synopsis
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Predictive Value of QFT(Diel et al AJRCCM Aug 2010)
954 close contacts
142 QFT-positive/TST-positive
Chemoprophylaxis RIF and/or INH
No active TB
51 QFT-positive(49 TST-positive)
Mean follow-up >3.5 yrTST cut-off >5mm
Not treated
17 developed active TB
343 TST negative
5 QFT-positiveTST-negative
Not treated
2 developed active TB
413 TST positive
Not treated Not treated
No active TB No active TB
198 QFT-positive 756 QFT-negative
Contact Investigation – Summary
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Predictive Value of QFT(Diel et al AJRCCM Aug 2010)
interferon antigen response listed under all state Medicare laboratory fee schedule
Medicare: $92.00 for most statesMedicaid: up to $86.59
some states not yet covered
Private Payers: Aetna: QFT a medically necessary preventive service for LTBI screening
in recent immigrants, injection-drug users, residents and employees of prisons and jails, HCW and military
United Healthcare: enrollees who are at increased risk for tuberculosis in all benefit plans
Blue Cross/Blue Shield: approved in some states
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True’ cost of a TST program
Lambert et.al. Infect. Control Hosp. Epidemiol. (2003)Annual cost of implementing and maintaining a TST program (4 hospital sites and 2 health departments):
Hospital: cost per HCW = $41 to $362Health Dept: cost per HCW = $176 to $264
TST supply costs accounted for less than 1.5% of the total cost of the TST program for all sites
QuantiFERON®-TB GOLD is cost effective!
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Cost-effectiveness of Interferon Gamma Release Assays vs Tuberculin Skin Tests in Health Care Workers
Marie A. de Perio, MD; Joel Tsevat, MD, MPH; Gary A. Roselle, MD; Stephen M. Kralovic, MD, MPH; Mark H. Eckman, MD, MS
Result:the QFT-GIT is the most effective and least costly strategy.
Conclusion: Use of the QFT-G and QFT-GIT leads to superior clinical outcomes and lower costs than the TST and should be considered in
screening non–BCG vaccinated and BCG-vaccinated new HCWs for LTBI.
Arch Intern Med. 2009;169(2):179-187
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Significant improvement in diagnosis of TB infection• Eliminate BCG and NTM false positives• QFT-Gold positive result is highly predictive of TB infection• More sensitive for active TB• Eliminates subjectivity