Oxford, UK & Marlborough, MA; June 27, 2011 – The interim findings of the SWITCH study, “Screening healthcare Workers with IGRA vs. TST: Impact on Costs and adHerence to testing”, were presented today at the Association of Professionals in Infection Control and Epidemiology (APIC) annual meeting by Dr. Edward Bernacki, M.D. MPH,
Executive Director, Health, Safety and Environment, The Johns Hopkins Health System and
University, and Director, Division of Occupational Medicine, Johns Hopkins University, School of
Medicine, a principal investigator of the study. The study compared costs and adherence to testing
when healthcare workers were screened for tuberculosis (TB) using the tuberculin skin test (TST) or
an Interferon Gamma Release Assay (IGRA).
The TST, which is over 100 years old, is still used by hospitals in the US for screening healthcare
workers for TB. The introduction of IGRAs provides hospitals with the potential to improve accuracy,
improve adherence to testing, and reduce costs. The Centers for Disease Control (CDC) recommend
that IGRAs can be used in all situations where the TST is currently used.¹
The primary objective of the SWITCH study is to compare “real world” costs and adherence rates of
running a TB screening program with the TST or IGRA. The study is being conducted over a multi-
year period at Johns Hopkins Medicine. The interim results compare testing with TST versus the
IGRA, showing materials costs and employee time consumed in completing TB screening. The
T-SPOT®. TB test was the IGRA used in the study. A systematic analysis was performed which
identified the institution?s actual costs associated with labor, follow-up (e.g. chest x-ray), treatment and
direct test costs.
The interim findings determined that a complete switch from the TST to an IGRA can improve testing
adherence at a lower cost. An IGRA virtually ensures one hundred percent adherence and eliminates
the costs of identifying and „chasing down? those healthcare workers who do not return for the reading
of the TST and repeat testing. Additionally, more employees were found uninfected with TB when
using an IGRA compared to the TST, which results in a reduction of chest x-rays and fewer healthcare
workers being placed on unnecessary therapy.
Dr. Peter Wrighton-Smith, CEO of Oxford Immunotec, commented, “Dr. Bernacki?s presentation of the
SWITCH study shows compelling evidence that implementing an IGRA for healthcare worker
screening is a successful cost-saving strategy for hospitals to employ.”
¹CDC MMWR 2010:59(No.RR-5):1-25.
About Oxford Immunotec
Oxford Immunotec Ltd., the T cell measurement company, is headquartered near Oxford, UK; its US
operations are based in Marlborough, MA. The company develops and sells clinical diagnostic
products based on its patented T-SPOT® technology, the first FDA-approved method for directly
quantifying antigen-specific T cells.
T-SPOT technology is a simple and extremely accurate method of studying a person?s cellular immune
response to infection and could be applied to diagnose and monitor any major disease driven by a
T cell response.
About T-SPOT®.TB test
The T-SPOT.TB test is an in vitro T cell measurement assay used for diagnosing TB disease and
latent TB infection and is the first product from Oxford Immunotec using T-SPOT technology. The
product offers unrivalled sensitivity with results unaffected by a patient?s immune status. The
T-SPOT.TB test is approved for sale in Europe, USA, Canada and over 40 other countries worldwide
and is designed to replace the 115 year old tuberculin skin test. It offers a substantially more accurate
and effective tool for controlling the spread of TB, addressing a market ex ceeding $1bn.
T-SPOT and the Oxford Immunotec logo are trademarks of Oxford Immunotec Ltd.