This study was conducted on 4,003 inhabitants of six villages, Southern County of Che Ju lsland from April 18 to July 30, 1974 with purpose of studying. Relationship between intradermal reaction and egg detection rate, Egg detection rate by the number of sputum examination on the same subject, Comparison of direct sputum examination method (Whole volume of sputum in vinyl bag pressed between petri dishes) with concentration (2per cent NaOH) method, Estimation of sensitivity and specificity of the intradermal test in screening paragonimiasis.

The results obtained are as follows:

1. Overall positive skin reaction rate was 57.7% and egg positive rate regardless of skin reaction was 17.1% the population studied.

2. Egg positive rate for negative skin reactors(wheal size smaller than 70mm²) was l0.l%, and that of positive reactors was 22.8%.

3. Positive skin reaction rate increased as age increased, egg positive rate, however, revealed rather inconsistent distribution by age.

4. The egg positive rate showed a tendency of increase by increase of wheal size, though not so remarkably.

5. 2.9% of egg positives by direct sputum examination method was negative when re-examined by concentration method; 2.6% of egg negative sputum by direct method was egg positive by concentration method. It was found that the sputa showing discrepant result by two different methods had only a few eggs in whole sputum collected.

6. Egg positive rate by single sputum examination was 8.l%, by two examinations 14.6% by three 19.2%, by four 24.5%, and by five examinations on the same individual was 20.5%.

7. The estimated sensitivity and specificity of the skin test were 76.5% and 42.7% respectively under the postulation that all infected persons could be detected by four sputum examinations.