Conversion of QuantiFERON-TB Gold Plus following Isoniazid Prophylaxis among Latent Tuberculosis Patients

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Sawang Saenghirunvattana, MD
Chitchamai Siangproh, BSc
Natsuda Wongkhot, BSc
Chonticha Noomcharoen, RN
Paulet Barro Ortiz, RN


OBJECTIVES: To evaluate the conversion of QuantiFERON-TB Gold plus (QFT-Plus) following Isoniazid prophylaxis among latent tuberculosis (LTB) patient.

MATERIAL AND METHODS: We conducted a case series starting in December 2016 up to the present March 2019. Twenty asymptomatic cases were identified to have had exposure to active tuberculosis (TB) infection, undergone chest x-ray and QFT-Plus test. Those with positive test QFT-Plus results with negative chest x-ray reports were prescribed with Isoniazid 300mg tablet once daily for nine months. Post prophylaxis, chest x-ray and QFT-Plus were repeated to determine the conversion results.

RESULT: All 20 participants were QFT-Plus test positive and chest x-ray negative. The average age was 47 ± 5.7 years and there were eighteen females and two males. Two had underlying conditions: valvular heart disease and peripheral neuropathy. All took the nine-month Isoniazid prophylaxis and repeated the QFT-Plus test and chest x-ray. Chest x-ray results again were all negative. Eighteen cases revealed persistence of positive QFT-Plus and two cases were negative. The initial conversion rate of QFT-Plus post treatment (2017) was ten percent. In the succeeding years (2018 and 2019), another ten percent conversion was reported and sixteen cases maintained their positive baseline score.

CONCLUSION: To our knowledge this clinical series is the first to report 20% conversion rate of QFT-Plus among LTB participants prescribed with a nine-month Isoniazid prophylaxis. This study only evaluated the conversion of QFT-Plus with LTB participants being treated with 9-month Isoniazid. As there is no gold standard on the definition and distinction of conversion and reversion, further studies are warranted to optimize the correlation between the efficacy of varied latent tuberculosis infection (LTBI) and TB treatment regimen and conversion of QFT-Plus results.


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Saenghirunvattana S, Siangproh C, Wongkhot N, Noomcharoen C, Ortiz PB. Conversion of QuantiFERON-TB Gold Plus following Isoniazid Prophylaxis among Latent Tuberculosis Patients. BKK Med J [Internet]. 2019Oct.24 [cited 2020Jul.15];15(2):145. Available from:
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1. World Health Organization. Global Tuberculosis Report 2018.Executive Summary. Geneva. Switzerland. 2018
2. Rajeswari R, Balasubramanian R, Muniyandi M, et al.Socio-economic impact of tuberculosis on patients andfamily in India. Int J Tuberc Lung Dis 1919;3(10):869-77.
3. Zenner D, Loutet MG, Harris R, et al. Evaluation of 17 yearsof LTBI screening in North West England: A retrospectivecohort study of reactivation. Eur Respir J 2017;50:1602505.
4. Houben RMGJ, Dodd PJ, The Global Burden of LatentTuberculosis Infection: A Re- estimation using mathematicalmodeling. PloS Med 2016;13(10):e1002152.
5. Rissel NL, Belcher BW, Bushyhead JB et al. The Accuracyof Tuberculin Skin Test: Self-Assessment by Adult Outpatients.Public Health Rep. July- August 1985; 100(4): 439-445
6. Lee E, Holzman RS. Evolution and Current Use of theTuberculin Test. Clin Infect Dis 2002;34:365-70
7. Yi L, Sasaki Y, Nagai H, et al. Evaluation of QuantiFERON-TBGold Plus for detection of Mycobacterium tuberculosisinfection in Japan. Sci Rep 2016;6:30617.
8. Azghay M, Bouchaud O, Mechai F et al. Utility of QuantiREFON-TB Gold In-Tube assay in adult, pulmonary andextrapulmonary, active tuberculosis diagnosis. Int J Infect Dis2016;44:25-30.
9. Kim HW, Kim JS. Treatment of Latent Tuberculosis Infectionand Its Clinical Efficacy. Tuberc Respi Dis (Seoul)2018;81(1):6-12.
10. Luetkemeyer AF, Charlebois ED, Flores LL et al. Comparisonof an interferon-y Release Assay with Tuberculin Skin Testingin HIV- infected individuals. AM J Respir Crit Care Med2007;175:737-42.
11. Saenghirunvattana S. Useful of Quantiferon G in managingsolitary pulmonary nodule of less than 3cm. Eur Respir J2011;38:2659.
12. Andrews JR, Hatherill M, Mahomed H, et al. The dynamicsof QuantiFERON-TB Gold IN-TUBE Conversion andReversion in a Cohort of South African Adolescents. Am JRespair Crit Care Med 2015;191(5):584-91.
13. Johnson JL MD, Geldenhuys H, Thiel B et al. Effects ofIsoniazid Therapy for Latent TB Infection on QauntiFERON-TBGold In-Tube responses in adults with positive TuberculinSkin Test Results in a High Incidence Area. Chest2014;145(3):612-7.
14. World Health Organization. Implementing the WHO Stop TBStrategy: A Handbook for National Tuberculosis ControlPrograms 2008. Geneva. Switzerland.
15. Saenghirunvattana S. Effect of Isoniazid prophylaxis onincidence of active tuberculosis among Thai HIV-infectedindividuals, J Med Assoc Thai 1996:79(5):285-7.
16. Centers for Disease Prevention. Severe Isoniazid AssociatedLiver Injuries among persons being treated for LatentTuberculosis Infection-United States-2004-2008. MMWRMorb Mortal Rep 2010;59(08);224-9.
17. Komiya K, Ariga H, Kurashima A, et al. Reversion rates ofQuantiFERON-TB Gold are related to pretreatmentIFN-gamma levels, J Infect 2011;63(1):48-53
18. Pettruccioli E, Vanini V, Chiacchio T et al. Analyticalevaluation of Quantiferon-Plus and Quantiferon-Gold In-Tubeassays in subjects with or without tuberculosis. Tuberculosis2017;106:38-43.