Diagnostic Kit for Human Tuberculosis Using the Combined ... · 1 · TB re-emerged as a major...
Transcript of Diagnostic Kit for Human Tuberculosis Using the Combined ... · 1 · TB re-emerged as a major...
Diagnostic Kit for Human Tuberculosis Using
the Combined ELISA & IFNγ Release Assay (An Innovative Solution for TB Control)
Current epidemiological status of TB
· TB re-emerged as a major global health threat · 1/3 of the world's population infected with Mycobaterium tuberculosis MTB · Around 9 million people develop the disease per year · An estimated 2-3 million people die of TB each year
Latent TB infections (LTBI)
· The majority of TB infections are latent TB · It may reactivate later in life · Tuberculin skin test (TST) was once the only means of diagnosing LTBI · TST problem is lack of specificity due to cross-reactivity
with BCG and other Mycobacterium.
Innovative Solution
· The Immune-based blood test, Interferon-Gamma Release Assays (IGRA), has dramatically improved the
diagnosis of LTBI.
www.biopanda.co.uk
Presentation of mycobacterium antigens
Memory T Cell
Antigen Specific T Cell produces IFNγ
APC
Principal of IGRA
1990 1995 2000 2005 2010
Global trends in case notification (black) & estimated TB incidence (green) rates, 1990–20101
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1 WHO report 2011 – Global TB control p40
Method Advantage Disadvantage
IGRA • Not affected by BCG & other Mycobacteria
• Higher specificity to LTBI & TB • Accurate indicator for LTBI & a
better predictor for the development of TB
• Fast result, less bias & can be repeated
• Freshly-collected whole blood required
• Basic laboratory & technical skills are required
• High cost
TST • A standard Test • Simple • Cheaper
• Affected by BCG & other mycobacteria
• Revisit doctor for results • Higher bias in
interpretation of result • Testing can’t be
repeated
Comparison between TST and IGRA
IFN γ
Responsible Diagnostic Solutions
Analytical sensitivity
Specimen Measurement range
Package Shelf life
0.15625 IU/ml Freshly-collected
Whole blood 0.15625 IU/ml
to 10 IU/ml 96 wells
(for 27 samples) 12 months
Unit 14, Carrowreagh Business Park Carrowreagh Road Belfast, BT16 1QQ United Kingdom Tel : +44 (0)28 95438774 E-mail: [email protected] Website: www.biopanda.co.uk
Whole blood sample collected
Overview of the IFNγ Assay Technology The TB-ELiFN kit is based on the combination of IGRA technology and
enzyme-linked immunosorbent assay (ELISA) test systems, to measure the interferon gamma (IFNγ) released by memory T cells in human whole blood through in-vitro stimulation with specific MTB antigens.
Sensitised T cells release IFNγ
Incubation in 3 tubes provided (16-20 hours at 37oC)
IFNγ production measured using TB-ELiFN
Results read using an ELISA plate reader
Results expressed as IU/ml
TB-ELiFN Features
Specific antigens employed in the kit are identified only in MTB; not in BCG strains or most non-tuberculous mycobacteria
No cross-reactivity is found with other cytokines, e.g. IL-2 (40 ng/ml), IL-4 (5 ng/ml), IL-5, IL-6, IL-8, IL-10, IL12 (100 ng/ml)
No separation of T cells is required Sensitivity at 94.23% is reached with active TB patients
A high throughput ELISA test system Specificity at 96.23% is reached with healthy volunteers
Standard provided in liquid form Stability: at least 12 months
Plasma specimen collected and assay performed