SciELO - Scientific Electronic Library Online

vol.28 issue1Overweight and obesity in children and adolescents: comparison of three classification criteria based on body mass indexThe public health care system and rehabilitation actions in Brazil author indexsubject indexarticles search
Home Page  

Services on Demand




Related links


Revista Panamericana de Salud Pública

On-line version ISSN 1680-5348Print version ISSN 1020-4989


BABOOLAL, Shirematee; RAMOUTAR, Dottin  and  AKPAKA, Patrick Eberechi. Comparison of the QuantiFERON®-TB Gold assay and tuberculin skin test to detect latent tuberculosis infection among target groups in Trinidad & Tobago. Rev Panam Salud Publica [online]. 2010, vol.28, n.1, pp.36-42. ISSN 1680-5348.

OBJECTIVE: To compare the QuantiFERON®-TB Gold (QFT-G) assay and tuberculin skin test (TST) in screening/diagnosis of latent tuberculosis infection (LTBI) among individuals in Trinidad & Tobago at high risk for TB. METHODS: A total of 560 individuals (TB patient contacts, HIV patients, health care workers, prison inmates, and TB patients [controls]) were recruited for the study. Blood was drawn and processed using the QFT-G assay, followed by immediate administration of TST solution on subjects' forearm. Data were analyzed with Epi InfoTM 3.5.1 software. Results were compared across the target groups using the chi-square test (P < 0.05). RESULTS: The QFT-G assay detected LTBI in 51% of the subjects (with most positive results occurring among the control group) whereas the TST detected it in 39.4% (P = 0.001). Overall, the QFT-G assay detected LTBI more frequently than the TST among all subjects except the control group, where detection favored the TST. The QFT-G assay produced indeterminate and nonreactive results in some HIV patients but required less turnaround time than the TST (23.3 h versus 70.2 h; P < 0.0001). The TST cost less per subject than the QFT-G assay (US $3.70 versus US $18.60; P = 0.0008). CONCLUSIONS: The QFT-G assay cost more but had a higher detection rate among most target groups and required less turnaround time than the TST. However, its sensitivity was lower among immunocompromised subjects. Therefore, the QFT-G assay should be used with caution for LBTI screening/diagnosis in resource-poor, high-HIV prevalence settings such as Trinidad & Tobago.

Keywords : Latent tuberculosis; tuberculin test; enzyme-linked immunosorbent assay; Trinidad and Tobago.

        · abstract in Spanish     · text in English     · English ( pdf )