MARLBOROUGH, Mass.--(BUSINESS WIRE)--The landmark SWITCH study, (Screening healthcare Workers with IGRA vs. TST: impact on Costs and adHerence to testing) has been published in the July issue of the Journal of Occupational and Environmental Medicine (JOEM), a leading journal for workplace safety in the US.
This study compared costs and adherence to testing when healthcare workers were screened for tuberculosis (TB) using the tuberculin skin test (TST) and the Interferon Gamma Release Assay (IGRA). The primary aims of this study were, for the first time, to systematically measure the cost of screening healthcare workers for TB infection using the TST and to determine the price point at which an IGRA is less costly than a TST.
The TST has been used in hospitals throughout the US for more than a half century to identify tuberculosis infection in employees. The TST has been perceived to be inexpensive, but has many logistical, clinical and adherence limitations. The development of IGRAs, such as the T-SPOT.TB test, has made screening for TB infection more accurate and logistically efficient, and screening using IGRAs is recommended in guidelines from the Centers of Disease Control and Prevention [1].
The SWITCH study results show that the perception of the TST being inexpensive are misplaced; the TST was shown to cost over $73 per person once all the costs of conducting screening using the TST are accurately measured. The use of an IGRA for employee health testing, instead of the TST, is cost saving at an IGRA test cost of $54.83 or less per test and results in higher completion rates because of the elimination of the need for a second visit (as is required to interpret the TST).
Dr. Edward Bernacki, Professor of Medicine and Executive Director, Health, Safety and Environment, The Johns Hopkins Health System and University; and Director, Division of Occupational and Environmental Medicine, Johns Hopkins University who was the senior author of the study commented “The SWITCH study is the first of its kind in that it sought to accurately measure all the costs of administering a program using a TST or an IGRA. Our study shows that when the time consumed in administering a TST program is accurately measured and expensed, TST screening is costly for a sizeable institution like ours, both in absolute terms (exceeding $1m annually) and on a per person basis ($73.20/person). Given that the TST material cost is relatively inexpensive, this high cost reflects the significant burden on staff time required to both administer and receive the TST.” He continued “The study also showed that our confidence in the TST is misplaced, with significant numbers of persons deemed infected by the TST now able to be classified as uninfected given the greater accuracy of the IGRA. The use of an IGRA should enable us to run our program more efficiently, at lower cost and with greater accuracy.”
Dr. Peter Wrighton-Smith, CEO of Oxford Immunotec and lead author commented “TB surveillance of healthcare workers is an important component of safeguarding their health at work. However, this job has been made more difficult than need be by using the antiquated TST. For the first time this study exposes the false economics of using the TST. Given the quantity of tests performed each year for employees all over the country, savings of millions of dollars could be realized by adopting IGRAs instead of the TST for this purpose whilst freeing up substantial amounts of time for other programs to improve employee health and wellness”.
“Screening Health Care Workers With Interferon-γ Release Assay Versus Tuberculin Skin Test: Impact on Costs and Adherence to Testing (the SWITCH study)“. Journal of Occupational & Environmental Medicine. 54(7):806-815, July 2012
As the article was selected for CME credits - it can be accessed free at: http://journals.lww.com/joem/pages/default.aspx
The article has supplementary online content which can be accessed free at: (http://links.lww.com/JOM/A95)
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Notes to Editors:
Background to the SWITCH study
TB surveillance of healthcare workers using the Tuberculin Skin Test (TST) both upon hiring and thereafter at regular intervals (based on the TB risk of the institution) is a cornerstone of TB surveillance and control in healthcare institutions [2]. An estimated 10m healthcare workers receive testing each year. The drawbacks of the TST for this purpose are well known and include variable specificity, particularly in previously BCG vaccinated persons, suboptimal sensitivity, the requirement for a repeat visit within 48-72 hours to read the test, the requirement for specially trained personnel to administer and read the test, and high inter and intra-reader variability [3].
Over the past few years new blood tests, called Interferon-gamma release assays (IGRAs), have been approved by the Food & Drug Administration (FDA) as aids in the diagnosis of TB infection. Two assay formats are available; the T-SPOT.TB test being one. The replacement of the TST with an IGRA could have a number of programmatic advantages for healthcare worker screening, such as the elimination of the need for a return visit to gain test results, the elimination of the requirement to have trained TST placers and readers, the ability to administer tests 5 days/week (TST placement on Thursday is currently problematic due to the need to have a weekend read), and the elimination of two-step testing for new hires. In addition, as the IGRAs have been shown to have high specificity that is unaffected by BCG vaccination, the use of IGRAs could potentially reduce the numbers of false-positive results obtained in foreign-born healthcare workers and thereby prevent unnecessary chest X-rays and chemoprophylaxis with its attendant risks.
The SWITCH (Screening healthcare Workers with IGRA vs. TST: impact on Costs and adHerence to testing) study was therefore conceived to systematically identify and then measure all the costs of screening the healthcare worker population in a large US hospital using either a TST or an IGRA and, in so doing, to build a model that could be used by other institutions across the US to judge the cost impact of making the switch to an IGRA. As part of the study, evidence was also gathered on the impact of using an IGRA on adherence to screening, as the aim of all employee health TB surveillance programs must be to ensure the highest completion rate possible. The study was designed to examine costs and adherence for annual screening (serial testing of current employees) and new hire screening (baseline testing of new recruits) both separately and in aggregate.
The study was conducted by the employee health department at the Johns Hopkins Healthcare System and the Johns Hopkins Medical School based in Baltimore, MD.
About Oxford Immunotec
Oxford Immunotec Ltd., a global immunology-focused diagnostic company, is headquartered near Oxford, UK; its US operations are based in Marlborough, MA. The company is developing novel new tests in the fields of infectious and immunological disease based primarily 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 and, as such, provides a unique methodology to diagnose and monitor diseases driven by a T cell response.
Oxford Immunotec’s primary product, the T-SPOT.TB test, is one of two Interferon-gamma release assays (IGRAs) which detect latent TB infection and are replacing the 90-year old tuberculin skin test currently used for this purpose. The World Health Organisation [4] estimated in 2006 that 50 million latent TB screening tests were performed each year, representing a greater than $1bn per annum market opportunity for TB testing globally. IGRAs are now endorsed in clinical guidelines in over 20 countries and the T-SPOT.TB test has now received regulatory approval in over 40 countries worldwide, including the US, Europe and China. In the US, the T-SPOT.TB test has its own CPT® code (86481) with recently increased CMS reimbursement of approximately $106/test. The T-SPOT.TB test is also covered in various other clinical lab fee schedules around the world.
As well as developing & selling tests in kit form, Oxford Immunotec also runs a testing laboratory business in both the US and the UK (Oxford Diagnostic Laboratories) designed to provide unparalleled levels of expertise, service, turnaround time and simplicity for physicians wanting to access immunological tests such as the T-SPOT.TB test.
T-SPOT and the Oxford Immunotec logo are registered trademarks of Oxford Immunotec Ltd.
CPT is a registered trademark of the American Medical Association
References
1. Centers for Disease Control and Prevention. Updated Guidelines for Using Interferon Gamma Release Assays to Detect Mycobacterium tuberculosis Infection — United States, 2010. MMWR 2010;59 (No.RR-5)
2. Centers for Disease Control and Prevention. Guidelines for preventing the transmission of Mycobacterium Tuberculosis in Health-Care settings, 2005. MMWR 2005;54 (No.RR-17)
3. Huebner RE, Schein MF, Bass JB. The Tuberculin Skin Test. Clin Infect Dis. 1993;17:968-75
4. WHO. Diagnostics for tuberculosis : global demand and market potential. 2006