Validity of a self-reported history of a positive tuberculin skin test. A prospective study of drug users.
OBJECTIVE
To define the prevalence of and factors associated with having a negative purified protein derivative (PPD) among persons who self-report a prior positive PPD and to define the safety of repeat testing in such persons.


METHODS
Observational cohort study.


METHODS
Methadone maintenance program with onsite primary care.


METHODS
Current or former drug users enrolled in methadone maintenance treatment.


METHODS
Structured interview, tuberculin skin testing regardless of self-reported PPD status, and anergy testing.


RESULTS
Nearly one third (31%) of participants who self-reported a prior positive PPD had a negative measured PPD, despite receipt of a "booster" PPD. A single participant (0.5%) blistered in response to the PPD without lasting ill effect. Participants with PPD results discordant from their history were more likely to be HIV-seropositive and nonreactive to the anergy panel. The discordance rate among HIV-infected participants was 43%, and was largely attributable to immune dysfunction. Among HIV-seronegative participants, the discordance rate was 27%. Recent crack-cocaine use was independently associated with discordance in the absence of HIV infection.


CONCLUSIONS
We confirmed that planting a PPD in patients who self-report a positive PPD history confers minimal risk. Substantial rates of discordance exist between self-reported history of a positive PPD and measured PPD status. Further research is needed to define the optimal management of PPD-negative patients who self-report a prior positive PPD and who have not received prior treatment for latent tuberculosis.
Kunins
Hillary V
HV
Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA. hkunins@montefiore.org
Howard
Andrea A
AA
Klein
Robert S
RS
Arnsten
Julia H
JH
Litwin
Alain H
AH
Schoenbaum
Ellie E
EE
Gourevitch
Marc N
MN
D000328:Adult; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000276:immunology / Q000523:psychology; D006801:Humans; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012650:Self Disclosure; D019966:Substance-Related Disorders / Q000150:complications / Q000523:psychology*; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000175:diagnosis*