[Tuberculin test responses of tuberculosis patients].
OBJECTIVE
To determine the response of tuberculosis patients to tuberculin skin tests.


METHODS
The results of skin tests used for initial assessment of tuberculosis patients in Catalonia were reviewed (Multicenter Tuberculosis Research Project). Negative skin tests were those with indurations < 5 mm; positive tests were those with indurations measuring > or = 5 mm. Individuals were classed as having or not having risk factors for developing tuberculosis and those without risk factors were classified by age, location and extension of tuberculosis.


RESULTS
Negative skin tests were seen in 1,566 patients (23%). Negative tests were more common in patients with risk factors, significantly so in those undergoing immunosuppressant therapy (50%) or with HIV infection (61%). Negative tests were less prevalent in patients with no risk factors (13%) and, among them, in children (1%), in patients between 15 and 29 years of age (10%) or in those with non-pulmonary forms (10%). Negative tests were significantly more prevalent among patients 60 to 74 years of age (27%), those over 74 (44%), and those whose disease was pulmonary and extrapulmonary (26%) or disseminated (64%). No significant differences in induration size of positive skin tests were observed for patients with and without risk factors (including HIV infection or non-infection). A normal distribution of induration size was observed in all groups.


CONCLUSIONS
A negative tuberculin skin test for initial assessment should be interpreted in function of the presence or absence of risk factors, age, location or extension of tuberculosis. When a skin test is positive, the response will be similar whether or not an immunodepressant factor is present.
Pina
J M
JM
Programa de la Tuberculosi de la Regió Sanitària Centre de Catalunya. Servei Català de la Salut. Institut Català de la Salut. España.
Domínguez
A
A
Alcaide
J
J
Alvarez
J
J
Camps
N
N
Díez
M
M
Godoy
P
P
Jansá
J M
JM
Minguell
S
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology