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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
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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 Company
A little history • • • In the 1980’s the need for a better test for TB • infection in cattle was addressed in Australia • • • The tuberculin skin test in cattle had very similar • problems to the TST in humans and thus a new • test was needed • I • But also was a very messy test to perform
History of QuantiFERON® 1980’s • Developed by Australian researchers at CSIRO for detecting TB in Australian cattle herds Early 1990’s • CSL (Australia) acquired exclusive license to patents; and undertook commercialization of a cattle diagnostic test and development of a human diagnostic for TB 2000 • Cellestis, founded by two of the inventors of the QuantiFERON® technology, was chosen to commercialize the human TB diagnostic, known as QuantiFERON® -TB
Skin Testing Cows Australia 1990’s • Injecting tuberculin from M. • bovis into the caudal fold • (base of tail) of a cow.
Tuberculosis (TB) Review • Bacterial infection caused by Mycobacterium tuberculosis complex organisms • M. tuberculosis, M. bovis, M. africanum • Infection may be either • Active (with all symptoms and highly contagious) • Latent (without any symptoms, not contagious) • Latent TB infection (LTBI) • Needs treatment • Progression to active disease • Treatment involves 6-9 months antibiotic therapy; new therapy once per week for 12 weeks.
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
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
Global travel makes it worse Journal of the American Medical Association
Transmission of TB Not infected Family, friends, workmates etc. exposed Infected, but no symptoms “Latent TB infection” If identified & treated they don't develop TB disease If not identified & treated ~10% develop TB disease during their lifetime Active TB: Infectious
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
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)
TB and the 21st Century QuantiFERON®-TB Gold ‘‘In-tube’
And counting… • 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 1,100,000 tests/year in the US
Principle use of QFT in the United States… by…Public Health Departments • for… • Contact Investigations • Homeless • Refugees • Recent Immigrants • TB/Chest Clinics for…HCW Screening • by… • Major University Hospitals & Medical Centers • VA Hospitals • Military Facilities • Foreign Students at University Hospitals for… Clinical & Immune Suppressed Patients • HIV & Other Infectious Disease Clinics • TNF inhibitors (Rheumatologists)
T-cells activate and secrete IFN-γ. Immunological Basis for QuantiFERON® Testing • In normal circumstances, there is no Interferon Gamma (IFN- ) within the blood. • In the presence of the TB specific antigens, T cells of infected persons are stimulated to produce IFN- • In the QFT test • whole blood is exposed to 3 TB specific antigens • T cells of infected persons are activated and secrete IFN- • Measurement of IFN- using an ELISA assay is the basis for the QFT test
QuantiFERON®-TB Gold Procedures & Guidance Blood Collection Laboratory ELISA Data Analysis
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
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 Blood Collection
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
After Blood Collection and Shaking Tubes can be held at Room Temperature for up to 16 hours Option 1: Within 16 hours of collection/shaking, tubes must be incubated at 37ºC for 16-24 hours Option 2: Following incubation, tubes have up to 3 days for transfer to lab for QFT ELISA
Data Analysis and Results • Results are reported as: • Positive • Negative • Indeterminate • Indeterminate • Low mitogen • High Nil
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)
Real World Experiences • NYC Dept. of Health • San Francisco Dept. of Health • University of Illinois Chicago • Cleveland Clinic
2nd Global symposium on IGRA’s (Dubrovnik, Croatia, June 2009)
Performance of IGRAs and the TST:An up-to-date TB Test Meta-Analysis RDiel, R Loddenkemper and A Nienhaus Evidence 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;
Key findings from meta-analysis:IGRA and TST specificity p<0.0001 *QFT significantly more specific than both the TST and T-Spot (p<0.0001)
Key findings: IGRA and TST Specificity How does this translate into false-positives per 1,000 tested people without TB? p<0.0001
IGRA Indeterminate rates from Diel et al, Chest, 2009 For both IGRAs there are significantly more indeterminate results in those immune suppressed
Cellestis Synopsis Negative and positive predictive value of a whole-blood IGRA for developing active TB - an update Diel R, Loddenkemper R, Niemann S, Meywald-Walter K, Nienhaus A Am J RespirCrit Care Med 2010. [Epub Aug 27, 2010] An analysis of 954 tuberculosis contacts comparing QuantiFERON® TB Gold (QFT®) and tuberculin skin test (TST) M31635074C
Contact Investigation – Summary 954 close contacts 198 QFT-positive 756 QFT-negative 142 QFT-positive/ TST-positive 5 QFT-positive TST-negative 51 QFT-positive (49 TST-positive) 413 TST positive 343 TST negative Not treated Not treated Chemoprophylaxis RIF and/or INH Not treated Not treated No active TB 17 developed active TB 2 developed active TB No active TB No active TB Mean follow-up >3.5 yr TST cut-off >5mm
Predictive Value of QFT(Diel et al AJRCCM Aug 2010) Contact Investigation – Results • QFT-negative contacts 198 QFT-positive 756 QFT-negative 5 QFT-positive TST-negative 51 QFT-positive (49 TST-positive) 413 TST positive 343 TST negative Not treated Not treated Chemoprophylaxis RIF and/or INH Not treated Not treated 2 developed active TB No active TB No active TB No active TB
Contact Investigation – Results • QFT-negative contacts • 55% of QFT-negative were TST-positive • No progression to active TB at 3.5 years • In this study, QFT demonstrates 100% NPV* 756 QFT-negative 413 TST positive 343 TST negative Not treated Not treated No Active TB No Active TB No active TB * Negative Predictive Value (NPV)
Contact Investigation – Results • QFT-positive contacts 198 QFT-positive 756 QFT-negative 142 QFT-positive/ TST-positive 5 QFT-positive TST-negative 51 QFT-positive (49 TST-positive) 413 TST positive Not treated Not treated Chemoprophylaxis RIF and/or INH Not treated 17 developed active TB 2 developed active TB No active TB No active TB
Contact Investigation – Results • QFT-positive contacts • All 19 untreated contacts who progressed to active TB were QFT-positive. • TST missed progression; • 11% missed @ >5mm • 47% missed @ >10mm 198 QFT-positive 142 QFT-positive/ TST-positive 5 QFT-positive TST-negative 51 QFT-positive (49 TST-positive) Not treated Not treated Chemoprophylaxis RIF and/or INH 17 developed active TB 2 developed active TB No active TB
Number of Contacts Needing Treatment to Prevent Progression to Active TB • QFT identified 100% (19/19) of contacts who progressed to active TB • TST @ >5mm cut-off missed 11% (2/19) • TST @ 10mm cut-off missed 47% (9/19) • By using QFT, at least 60 fewer contacts required treatment
Be Confident Using QFT Predictive Value of QFT(Diel et al AJRCCM Aug 2010) • QFT demonstrated 100% NPV in this study • No contacts who tested QFT-negative developed TB • Lower program costs by only treating those who really need it • Recommendations & Guidelines suggest QFT can be used as a replacement for the TST • US: Centers for Disease Control & Prevention • Japan: Kekkaku 2010
Sahni et al 2009. Infect. Control Hosp. Epidemiol. • 2,048 QFT results on HCWs • 90 were QFT positive • INH acceptance compared to when using the TST • Acceptance increased from 11% to 52% • Reduces the “I am positive because of BCG” effect
CDC Guidelines - 2010 • IGRAs may be used in place of (and not in addition to) TST in all situations in which CDC recommends TST • Which IGRA or TST to be used should be based on the context for testing, test availability, and overall cost effectiveness of testing. • Neither IGRAs, nor TST should be used for testing persons who have a low risk of TB infection • IGRA is preferred • for testing persons from groups that historically have poor rates of return for TST reading. • for testing persons who have received BCG • TST is preferred • for testing children younger than 5 years old ‘QFT-G can be used in all circumstances in which the TST is currently used’ …now able to detect TB with greater specificity than previously possible’
Role of Public Health Public Health in charge. CDC involved only in case of outbreaks Reference – Maryam Haddad, CDC
Role of Cellestis • Have Program Coordinator on site who works closely with DOH • Work through checklist to mobilize resources needed • Ensure • QFT kits are available on site • Blood draw logistics in place including trained phlebotomists, blood collection kit (butterflies etc…) • Identify preferred laboratory for QFT testing • Coordinate collection, tube handling and shipment to testing laboratory • Be a liaison with lab and DOH to ensure data integration
Reimbursement for Diagnostic Use • CPT Code: 86480 • Tuberculosis test, cell mediated immunity measurement of gamma interferon antigen response • listed under all state Medicare laboratory fee schedule • Medicare: $92.00 for most states • Medicaid: 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
True’ cost of a TST program QuantiFERON®-TB GOLD is cost effective! • 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 $362 Health 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