To determine if the booster effect of a repeat Mantoux tuberculin skin test can be used as a diagnostic criterion of tuberculosis in children and to determine the factors affecting the booster phenomenon.
This is an experimental study conducted at a University Hospital out patient department and non goverment organization (NGO) medical clinic. Six hundred seventy four (674) children aged 6 months to 19 years old seen as out patients were screened for tuberculosis. A two step tuberculin test was done to determine if the initial tuberculin reaction was truly negative. Factors affecting booster response in patients who were given a booster test were assessed.
Out of the 339 non reactors to the initial Mantoux tuberculin skin test, 240 (70.8%)had a positive booster result. Neither BCG vaccination,time of boosting and nutritional status were related to the incidence of boosting. There was a correlation between age, sex, presence of tuberculosis disease and positivity of a repeat tuberculin skin test. Factors such as history of exposure, signs and symptoms suggestive of tuberculosis (TB) and abnormal chest radiographs are important parameters that helped distinguish between boosting secondary to other causes from true conversion which indicates recent infection with M. tuberculosis.
The presence of TB disease is related to the positivity of a repeat Mantoux Tuberculin skin test. Factors such as exposure, abnormal radiographs, signs and symptoms suggestive of TB are important parameters that affected the booster effect.
There is a need to do a repeat tuberculin skin test in contacts of active cases of TB who had an initial negative reaction.
M.B. Zerda, None.