Simultaneous Mantoux and Vollmer Patch Tests in 855 School Children

¹ School Health Service, Los Angeles City Board of Education.

With the decreasing morbidity and mortality of tuberculosis, the tuberculin skin test assumes increasing importance. Accurate knowledge of the presence of tuberculin hypersensitivity is essential for those who desire to treat recent converters or to administer BCG. Many scientific, industrial and medical legal problems demand accurate evaluation of tuberculin hypersensitivity. Determination of accurate tuberculin hypersensitivity in younger age groups is especially valuable for diagnostic purposes in view of the large percentage of negative reactions expected.

A study was made in two Los Angeles City schools, in an effort to determine whether or not the patch test (Vollmer) could be substituted for the intracutaneous test (Mantoux). It was felt that the patch test might have advantages in the ease of administration and in acceptability to the student and his parents. The two tests were given simultaneously, using an intracutaneous test (Mantoux) of 0.00025 mg. PPD (equal to 12.5 TU) and a patch test (Vollmer) (probably equal to 2.5 TU). The skin test suffered the disadvantage in that in about 10 per cent of the tests the patch became detached before the proper time interval had lapsed. Of 855 students so tested and included in this study, 83 reacted to both tests; 113 to the intracutaneous test but not to the patch test; and 3 reacted to the patch test but not to the intracutaneous test. In general, it was noted that where the intracutaneous reaction was markedly positive, the patch test was also usually positive, but where the intracutaneous reaction was less marked, the patch test did not cause a reaction. When the patch test is positive, the intracutaneous is almost certain to confirm tuberculin sensitivity.

The group of intracutaneous positives of minimal readings (one plus and two plus) holds special significance. If the individuals in this group had been given only the patch test many would have gone unrecognized as being sensitive. The authors acknowledge that in a clinical situation dealing with individual contact patients where higher tuberculin dosages could be used in repeat testing to rule out false negatives, the patch test is satisfactory. They are not convinced, however, that a high proportion of clinicians routinely follow a negative patch test with intradermal tests of higher tuberculin strength to exclude the possibility of a false negative reaction.

The group of intracutaneous positives of minimal readings, moreover, is apt to be productive of active cases. The authors maintain that the testing situation described herein is comparable with the previous screening in Los Angeles schools where 20 active cases with prior intracutaneous minimal readings (one plus and two plus) were determined out of 45 active cases with prior readings of all degrees.

Any failure to detect active cases far less pronounced than is indicated above would invalidate the use of the patch test in spite of this test's greater economy as to expense and work load. It is concluded, therefore, that intracutaneous tuberculin testing should remain the method of choice in Los Angeles City schools. It is acknowledged that in other testing situations the patch test may be a useful procedure.