Need for Different Cutoff Values for Reading Mantoux Test with 2TU and 5TU PPD
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To compare the tuberculin reaction of 2 tuberculin unit (TU) with 5TU purified protein derivative (PPD) (both calibrated against RT 23) in healthy children.
This was a cross sectional study done in the pediatric outpatient department of a tertiary care teaching hospital. Seventy healthy siblings of the children attending pediatric outpatient department in the age group of 1 to 12 y were enrolled. The exclusion criteria included previously diagnosed tuberculosis patients, malnutrition diagnosed according to the WHO classification, history of drug intake like steroids, recent history of measles, any skin lesions over forearm, history of fever, contact with tuberculosis and previous mantoux testing. The study was conducted wherein each child was subjected to simultaneous testing with 2TU and 5TU by standard technique. The reactions to both the tests was read at 48–72 h. Children with induration ≥10 mm were evaluated for tuberculosis by taking chest x-ray, gastric lavage or sputum smear examination for acid fast bacilli (AFB).
Considering ≥10 mm induration as positive, subjects positive with 5TU were 7 (10%) and 2TU was 1(p value = 0.031); thus, there is no agreement between the two methods (McNemar’s test). Comparing the mean diameter of induration of 2TU and 5TU (p < 0.001, Wilcoxon test), signified no agreement between the two strengths. Bland-Altman plot and kappa statistic showed no agreement between the two strengths.
Cutaneous hypersensitivity to 2TU PPD is not comparable to that of 5TU PPD.
KeywordsChildhood tuberculosis Mantoux test 2TU and 5TU PPD tests
SMR: Conceptualized the study. NK, GG and SMM: Finalized the methodology. NK and GG: Collected the data. SMR: Drafted the manuscript with inputs from NK, SMM and GG. SMR, SMM and NK: Planned and conducted the statistical analysis. SMR and SMM critically reviewed the article for intellectual content. All authors approved the final paper. SMR shall stand as the guarantor for this paper.
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- 1.Global Tuberculosis Control. Geneva: WHO; 2014. Available at: http://www.who.int/tb/publications/global_report. Accessed on 1st September 2016.
- 2.Guidance for National Tuberculosis Programmes on the Management of Tuberculosis in Children. World Health Organization. 2006. Available at: http://www.whqlibdoc.who.int/hq/2006/WHO_HTM_TB_2006.371_eng.pdf. Accessed on 1st September 2016.
- 3.National Guidelines on Diagnosis and Treatment of Pediatric Tuberculosis. Directorate General of Health Services, Central TB Division, Ministry of Health and Family Welfare, Government of India. Available at: http://www.tbcindia.nic.in/Paediatric guidelines_New.pdf. Accessed on 1st September 2016.
- 5.Guidance for National Tuberculosis Programmes on the Management of Tuberculosis in Children. Second Edition. World Health Organization. 2014. Available at: http://www.who.int/tb/publications/childtb_guidelines/en/. Accessed on 1st September 2016.
- 6.Revised National TB Control Programme. Technical and Operational Guidelines for TB Control in India. Directorate General of Health services, Central TB division. Ministry of Health and Family welfare. Government of India. 2016. Available at: http://www.tbcindia.nic.in/showfile.php?lid=3216. Accessed on 1st September 2016.
- 7.Chadha VK, Jagannatha PS, Nagaraj AV, Narayana Prasad D, Anantha N. A comparative study of tuberculin reactions to 1 TU and 2TU of PPD - RT23. Indian J Tuberc. 2000;47:15–20.Google Scholar
- 8.Lee JH, Oh SH. Tuberculin reactivity to 2TU of PPD RT23 following intradermal BCG vaccination in neonates. Korean J Pediatr. 2000;43:1418–22.Google Scholar
- 9.Jo DS, Lee KM, Lee DY, Kim JS. Comparative reactivity of 2TU and 5TU PPD skin tests. Korean J Pediatr. 2000;43:638–43.Google Scholar
- 10.Reyes CM, Sanchez L, Ong-Lim AL, Gonzales LM. A paired comparison of tuberculin skin test results in children with clinical manifestations of tuberculosis using 2TU and 5TU tuberculins. PIDSP J. 2011;12:56–66.Google Scholar
- 12.Muñoz-Barret JM, Macías-Hernández AE, Hernández-Ramos I, et al. Comparative tuberculin reactivity of two protein derivatives. Rev Investig Clin. 1996;48:377–81.Google Scholar