| Abstract: | A new batch of PPD tuberculin, RT 23, prepared at the request of UNICEF by the Statens Seruminstitut, Copenhagen, has been compared with previous batches of tuberculin from the Statens Seruminstitut and with the International Standard for the Purified Protein Derivative of Mammalian Tuberculin. The comparisons were made by intradermal tuberculin testing. The majority of tests were carried out in human subjects with various types and levels of tuberculin sensitivity—namely, tuberculous patients in the Netherlands; BCG-vaccinated as well as spontaneously tuberculin-sensitive army recruits in the Netherlands; BCG-vaccinated schoolchildren in Denmark; population groups in the tropics (Mauritius and Nigeria) including a high proportion of persons with low-grade sensitivity. In addition, comparisons were made in guinea-pigs sensitized in different ways. |
