THE 5 TU versus the 10 TU intradermal tuberculin test.

With the growing demand in practical tuberculin-testing work for an effective single-dose intradermal test to replace the serial-dose procedures, the 5 TU and 10 TU doses have both been used for single-dose tests in recent years. The present study was undertaken for the purpose of determining the difference in the effects of these two doses.The material was collected by testing large general population groups participating in the Danish mass campaign in two areas in Jutland; 5 TU and 10 TU were given to alternate persons. Results are presented for 3,764 adults, none of whom gave a history of previous BCG vaccination.With either dose, the population groups were clearly separated into two groups, reactors and non-reactors. The average diameter of reactions for 10 TU was larger by about 2-3 mm than for 5 TU, and the frequency of bullous reactions was only slightly greater with the stronger dose.The two known sources of tuberculin sensitivity in Denmark, apart from BCG, are infection with human and with bovine tubercle bacilli. As both appear to result in a degree of sensitivity demonstrated about equally well with either 5 TU or 10 TU, either dose would seem to be suitable as a single-dose test for tuberculin-testing surveys in similar general populations.