Abstract

This study is planned to find out the factors that could be influential in the interpretation of, Tuberculin Test (TT) in our country. TT was performed with 5 TU PPD (RT23-Tween 80) solution to 2306 male (81.3%), 529 female (18.7%), totally 2835 people (between ages 6-82, average age: 25± 13.9). Chest X-rays were obtained from the ones 11 years old. Average enduration was found to be 11.95±6.74 mm (0-30 mm). Ratio of anergic cases was 16.4%. Diameter of enduration was 10 mm that in 67.3% and it was 12 mm in 54.2% of the cases. Ratio of not having any BCG vaccine scar was 8.8%, ratio of having 1, 2, 3, 4 and 5 scars were 42.8%, 31.6%, 13.4%, 3.3% and 0.1% respectively. An increase was detected in diameters of TT enduration with increasing age and number of BCG scars (r=0.43, p=0.000 and r=0.23, p=0.000 respectively). There was a significant increase in enduration when the number of scar is more then one (p=0.000). Enduration 10 mm was present in 70.1% of males and 55.0% of females(p=0.000). Ratio of positivity (10 mm) was 23.1% in people <18 years old but it was 76.9% in people >18 years old; this difference was statistically significant (p=0.000). New values are developed for interpretation of TT results and for determining the border of positivity by taking age, sex and number of BCG scars into consideration. This table of normal values could assist in interpretation of TT data in our country where the disease is endemic and routine BCG vaccination is done.