Evaluation of the clinical usefulness of mycobacterial skin test antigens in adults with pulmonary mycobacterioses.
A double-blind, multicenter study was conducted to evaluate the usefulness of mycobacterial skin test antigens for the specific diagnosis of adult pulmonary mycobacterial disease. The skin test antigens used were PPD-T (M. bovis) and PPD-B (M. intracellulare), made bioequivalent to 5 TU PPD-S through bioassay in human subjects. Of the 192 adults (18 yr of age or older), those with disease caused by M. tuberculosis (MTB) had significantly larger reactions to PPD-T than did those with disease caused by nontuberculous mycobacteria (NTM) or those with negative culture results (NEG)(13.41 mm versus 4.87 and 4.96 mm, respectively, p less than 0.001). The mean induration to PPD-B in NTM was not different from that in MTB or NEG. Defining a "positive" to be greater than or equal to 10 mm induration and a size difference of greater than or equal to 3 mm between PPD-T and PPD-B, the sensitivity, specificity, and positive predictive value (PPV) for PPD-T in diagnosing MTB versus NTM was 29, 90, and 75%. Corresponding values for PPD-B and NTM disease were 70, 61, and 64%. Dual testing was less useful in distinguishing disease caused by any of the mycobacteria from NEG. Although the sensitivity of PPD-B, made bioequivalent to PPD-S, was high, the specificity and PPV were low. We conclude that this preparation of PPD-B is no more useful in distinguishing adult pulmonary disease caused by NTM than is PPD-T alone.
Huebner
R E
RE
Division of Tuberculosis Elimination, Centers for Disease Control, Atlanta, Georgia 30333.
Schein
M F
MF
Cauthen
G M
GM
Geiter
L J
LJ
Selin
M J
MJ
Good
R C
RC
O'Brien
R J
RJ
D004311:Double-Blind Method; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis*; D015269:Mycobacterium avium Complex / Q000276:immunology; D015270:Mycobacterium avium-intracellulare Infection / Q000175:diagnosis*; D009163:Mycobacterium bovis / Q000276:immunology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014373:Tuberculin / Q000276:immunology*; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
D014373:Tuberculin