The accuracy of the field diagnosis is of crucial importance in the successful implementation
of a screening programme. In Sri Lanka, the feasibility of using primary health care workers
for oral cancer and precancer screening was pilot tested between 1980 and 1982. This
paper analyses in detail the categories of false positives referred and the false negatives
detected following screening. Among 660 subjects who arrived at the referral centre
following screening, 64 (10 per cent) had no apparent oral lesion. The predictive value …