Use of IGRA for TB Infection Screening

State: FL Type: Model Practice Year: 2013

Tuberculosis (TB) is still occurring in the United States especially among foreign born or those who have certain medical conditions. TB case rates are higher in Palm Beach County compared to the US national average. Palm Beach County’s population is over 1 million. Many migrant workers, immigrants and refugees from various countries with a high rate of tuberculosis live in and visit Palm Beach County. The Palm Beach County Health Department provides primary care including maternal and pediatric services to many of these individuals who are at high risk of developing this TB disease. Annually about 1200 individuals from Cuba, Haiti and many Asian countries are seen at our refugee clinic. Until 2010, screening for the TB infection was done with the PPD test which has some limitations for identifying this infection. Many of these individuals who tested positive with the PPD may not have the TB infection because the PPD solution contains many mycobacterium antigens other than tuberculin bacilli. In some cases the positive PPD could be due to the BCG vaccine they received in their country of origin. Patients who are screened with PPD have to come to the clinic twice for testing, once for placing the PPD and a second visit for reading the test. For individuals who test positive through the PPD, medical evaluation with a chest X-ray is required. If the chest x-ray is normal and they have no symptoms suggestive of TB preventive therapy is 9 months of Isoniazide (INH). Main objectives of the practice were as follows: 1) To screen the high-risk population for TB infection with a more specific test 2) To achieve a higher percent of individuals completing the preventive therapy for TB infection. A pilot study was started in the Palm Beach County refugee clinic of testing with IGRA (Interferon Gamma Release Assay) in June 2011. We tested individuals older than 5 years of age with IGRA test to obtain greater specificity and other logistic advantages in identifying the TB infection. Individuals whose IGRA tests were positive were started on preventive therapy after medical evaluation. These individuals were counseled due to having TB infection as determined by their positive IGRA. The majority of these patients are asymptomatic hence acceptability of taking INH for 9 months is higher if the screening test is more specific. Data was collected on age, country of birth, gender, zip code, Tb screening test results and chest x-ray assessment. We established a procedure to implement this practice in the existing services and developed the educational material for patients. We trained the clinic staff on IGRA testing, interpretation and how to perform follow ups on positive results. The cut off for a positive PPD was 10 mm or more in 2010 (CDC definition). The positive IGRA result was reported by a lab performing the test. Monthly visits were monitored for any patients who did not show up for their appointments. We tested all (100%) the individuals who came to our refugee clinic from June to November 2011. Four hundred and one (401) individuals older than 5 years of age were tested and 3.5 % (14) had a positive IGRA result and 70% completed therapy. In contrast, in 2010 patients with similar demographics at the same refugee clinic were screened with the PPD test and 15.7 % (66) tested positive and less than 10% started on preventive therapy. Although many of these individuals with a positive PPD may not have had TB infection, they all had multiple visits to the Health Department for PPD testing and reading, medical evaluation with the clinician, chest X-ray and lab. The reduction of false positive TB infection cases saves staff time and is more convenient for patients with a reduced number of visits and less preventive therapy for 9 months. Our Latent Tuberculosis Infection (LTBI) clinic visits reduced from 66 patients to 14 patients in just 6 months in one clinic. This practice of screening individuals with positive IGRA who are at high risk of TB infection has been demonstrated to not only to be cost effective for the health department, but also beneficial to patients by identifying and treating the true positive TB infection cases. We have implemented this practice at all of our clinics. The biggest challenge with implementation of practice was the ability of drawing blood by mid-afternoon so that blood could be shipped on the same day to lab.
ResponsivenessThe public health issue that this practice addressesThis practice addresses the issue of reducing the burden of TB disease by screening the individuals who are truly at high risk of developing tuberculosis disease and offering them preventive therapy. Tuberculosis disease is a growing concern in South Florida as it has visitors and immigrants from countries with high rates of Tb. The process used to determine the relevancy of the public health issue to the community More than two thirds of our Tb cases are among the foreign born and most other cases are among the individuals who are high risk for Tb infection due to their medical conditions. Screening the high risk individuals for TB infection is necessary so that we can reduce Tb disease transmission in the community How the practice address the issueOne of the strategies to control TB disease is to screen the individuals with a more specific test such as IGRA. This screening helps to identify and counsel the individuals who are positive with IGRA test, have a normal chest x-ray and have no symptoms of TB to offer them preventive therapy with INH and follow them to complete this therapy. Even though there is an effective preventive therapy available, patients are not convinced that they have the TB infection since they do not exhibit TB symptoms. A blood test specifically for tuberculin bacilli which identifies the TB infection is helpful to many patients in making their decision to start and complete the preventive therapy. Innovation Evidence based strategies used in developing this practice. New and improved tuberculosis diagnostics: evidence, policy, practice, and impact Pai, Madhukar; Minion, Jessica; Steingart , Karen; Ramsay, Andrew Infectious Diseases: May 2010 Vol 16-Issue 3-p 271-284 The practice is new to the field of public health Process used to determine that the practice is new to the field of public health Medical literature and CDC documents were reviewed. One of the articles on cost effectiveness of IGRA was presented at our Journal Club by a public health resident. Coordinators of the project attended a TB conference where the many advantages of the IGRA test as a screening test for TB infection for the high risk population was presented and discussed. Even though this test is available by commercial labs, many practitioners are not familiar with its application and cost effectiveness of its use as screening tool for identifying TB. How this practice differ from other approaches used to address the public health issueIGRA testing utilizes targeted testing by utilizing logistic and efficiency advantages over screening with PPD
Primary stakeholders Palm Beach County Health Department LHD's role The County Health Department’s role is mainly to be Coordinator and facilitator for the practice. This practice had broader application with community partners and providers. We have started to implement this practice through communicating and partnering with Palm Beach County Medical Society, the Medical Pediatric Society and other medical providers who partnered with us for H1N1 flu vaccination program. We have many community sites where migrants and other individuals with insurance seek medical care. This practice has been shared with primary care providers, urgent care centers, walk-in clinics and other sites that particularly see high risk population who should be screened for TB infection. Palm Beach County Health Department has done many projects with our community partners and we have the structure in place to work with community partners through coalitions and other agencies that provides care to high risk individuals. Stakeholders/partners The role of the stake holder is to implement this practice and provide feedback and evaluation of the practice in the community setting. We can provide technical assistance and share our experience, information and educational materials with them Learned learned Lessons we have learned are that it takes time to implement new strategies, to gain partners’ commitment to the cause, to prove how it benefits them and the population they serve. The biggest challenge with implementation of this practice was the ability of drawing blood by mid-afternoon so that blood could be shipped on the same day to the reference lab. The following steps were taken to start this practice in the Palm Beach County Community Health centers: Task 1. Review of the literature for screening for Tb infection with IGRA among high risk population. (January-February 2011) Task 2. Meeting to explore lab capability of doing the IGRA test. We met with lab and clinic staff to explore the lab capability to do this test. Also explored where to get the funding for this practice (February-March 2011) Task 3.Discussion with the refugee program staff at the bureau of TB at Department Of Health (March 2011) Task 4. Meeting with clinic administration staff and lab director to discuss the feasibility of testing with IGRA on refugee clinic patients (March-April 2011) Task 5. Writing and modifying the procedure for clinic flow with integration of IGRA testing incorporated in existing procedures. Guidelines on interpretation of IGRA test including the follow up of the individuals with indeterminate and borderline tests. (April-May 2011) Task 6. Developing patient education materials (May 2011) Task 7. Setting up data collection procedure and creating database for analysis. (May -June 2011) We implemented this practice at all of our clinics. In 2012, from January to September 30 over 3000 IGRA tests were done at various clinic sites. Time frame for carrying out the tasksTask 1.(January-February 2011) Task 2.(February-March 2011) Task 3.(March 2011) Task 4.(March-April 2011) Task 5.(April-May 2011) Task 6.(May 2011) Task 7.(May -June 2011) Our next step after implementing this practice at all of our clinics is to expand and bring this practice to the community sites as well. Implementing Succinct outline of some basic steps 1.Develop guidelines and procedure for incorporating IGRA testing within existing services for refugee clinic. 2.Guidelines on interpreting of IGRA results and follow up of positive tests 3.Provide training to staff on these guidelines and procedures 4.Creating data base for collecting the information on patients tested for IGRA test 5.Analysis of the data and writing report on findings 6.Sharing the findings of the data with staff at clinic, managers and Bureau of Refugee. 7.Presentation of findings at executive leadership meeting to propose and implementation of this practice at all the clinics at the Palm Beach county Health Department Lessons learned Lessons we have learned are that it takes time to implement new strategies, to gain partners’ commitment to the cause, to prove how it benefits them and the population they serve. The biggest challenge with implementation of this practice was the ability of drawing blood by mid-afternoon so that blood could be shipped on the same day to the reference lab. Since all the staff know this requirement we are able to accommodate the field blood draw. In near future we will be doing this test in house Cost of implementation Funding for IGRA test was provided by refugee program at DOH as reimbursement for the IGRA test instead of PPD. Cost of the IGRA test was offset by paying for the fewer chest X-ray done with IGRA test. Cost of IGRA test was $ 48.50 per test by the lab. Lab provided the shipping materials including shipping cost. In Kind: Clinic staff has to do an additional lab requisition which may have added half minute per patient. Labels for the requisition are pre-printed hence staff just have to check the test ordered. Tubes to collect the blood specimen were about 30 cents per tube. Lab tech was drawing the blood for other lab tests hence no extra time except when test has to be repeated due to borderline or indeterminate test results. Cost of Lab staff time that handled, shipped and other related duties was about $ 3200 for Palm Beach County Health Department.
Objective 1: To screen the high-risk population for TB infection with a more specific test Our evaluation consisted of measuring what percent of population who came to refugee clinic above 5 years of age were screened by the IGRA test. We were able to use IGRA to screen for TB infection in 100% of patients who were seen at refugee clinic from June to November 2011. This practice is still on-going but we have collected data for this specific time period. We collected the data from refugee clinic patients on demographic information including their country of birth and when they entered in US. This data was entered in Epi Info along with their IGRA result, chest X-ray and medical evaluation information. We also collected information regarding if the patient kept the appointment for LTBI clinic and if they were started on completed preventive therapy. We shared the data with the executive leadership for Palm Beach County and clinic staff and with community partners Objective 2: To achieve a higher percent of individuals completing the preventive therapy for TB infection. What percent of patients who were tested positive with IGRA were medically evaluated and started on preventive therapy.Outcome evaluation: There were 14 individuals with positive IGRA test during this period. Two of the patients had history of TB disease and have completed TB treatment in their country and 2 could not receive treatment due to contraindications due to other medical conditions. Ten of these individuals met criteria for starting on preventive therapy with INH for 9 months. Seven (70%) of 10 IGRA positive completed 9 months of preventive therapy. One patient refused to take preventive therapy, one moved out of area to go back to their country of origin and one was lost to follow up.
Stakeholder commitment Yes, we have stakeholder’s commitment to implement this practice. We have implemented this practice at other clinic sites and other specialty clinics. SustainabilityBy utilizing this IGRA test there is cost savings for the health department and there is increased convenience for the patient by decreasing the number of visits and unnecessary treatment of patients who are not truly positive. In the future, the health department will be able to recuperate the cost for uninsured patients by billing those who have insurance. Additionally, we improve compliance of completing treatment which cuts down cost by avoiding resistance to first line medications. Since we provide full primary services, we have implemented this program county wide at our health centers targeting especially our HIV clinic, maternity and adult medical high risk patients for TB disease and infection. These same cost savings can be applied to the private sector and to our non-profit partners who provide care to high risk individuals such as migrant centers and church based clinics.
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