Variability of the QuantiFERON®-TB gold in-tube test using automated and manual methods.

Background: The QuantiFERON®-TB Gold In-Tube test (QFT-GIT) detects Mycobacterium tuberculosis (Mtb) infection by measuring release of interferon gamma (IFN-γ) when T-cells (in heparinized whole blood) are stimulated with specific Mtb antigens. The amount of IFN-γ is determined by enzyme-linked immunosorbent assay (ELISA). Automation of the ELISA method may reduce variability.

Within-subject interlaboratory variability of QuantiFERON-TB gold in-tube tests.

Background: The QuantiFERON®-TB Gold In-Tube test (QFT-GIT) is a viable alternative to the tuberculin skin test (TST) for detecting Mycobacterium tuberculosis infection. However, within-subject variability may limit test utility. To assess variability, we compared results from the same subjects when QFT-GIT enzyme-linked immunosorbent assays (ELISAs) were performed in different laboratories.

Public health delivery systems: evidence, uncertainty, and emerging research needs.

The authors review empirical studies published between 1990 and 2007 on the topics of public health organization, financing, staffing, and service delivery. A summary is provided of what is currently known about the attributes of public health delivery systems that influence their performance and outcomes. This review also identifies unanswered questions, highlighting areas where new research is needed.