title: Implications of simultaneous tests for tuberculin and non-tuberculous mycobacteria antigen in the elderly.
abstract: It is well established that old people living in institutions are more susceptible to tuberculous reactivation and exogenic infection than the general population. Therefore, annual screening with a tuberculin (T) skin test is suggested. Unfortunately, the specificity and sensitivity of this test is limited because of cross-reactivity with non-tuberculous mycobacteria (NTM) and anergy. We therefore investigated the possibility that a simultaneous test with NTM antigen might be helpful in the interpretation of the T test in the elderly. We tested 220 inhabitants of a geriatric institution in Israel simultaneously with T and Mycobacterium scrofulaceum sensitin (S). Ninety-six subjects reacted to the T test, and 64 of them reacted to S as well. In this last group, 38 reacted more to T, 22 more to S, and 4 reacted equally to both antigens. Of the 124 subjects who did not react to T, 24 did react to S and 123 were retested with T. Twenty-two of the latter group had a positive booster effect, but 9 of the positive booster responders initially reacted to S. The difference between the proportions of the positive booster effect in the responders and the non-responders to S was significant. We conclude that in an area where infection with NTM is present a simultaneous S test may clarify the meanings of initial and booster-positive responses to T in the elderly, as well as exclude anergy when the T test is negative.
authors.affiliation: Chest Department, Meir General Hospital, Sapir Medical Center, Kfar Saba, Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Shachor
authors.forename: V
authors.initials: V
authors.lastname: Dunovets
authors.forename: S
authors.initials: S
authors.lastname: Poreh
authors.forename: C
authors.initials: C
authors.lastname: Shoham
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology; D000941:Antigens / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D003429:Cross Reactions; D005260:Female; D006801:Humans; D008297:Male; D015359:Mycobacterium scrofulaceum / Q000276:immunology*; D012680:Sensitivity and Specificity; D012882:Skin Tests; D014374:Tuberculin Test
chemical_list: D000941:Antigens; D000942:Antigens, Bacterial; C012031:sensitin