1 Department of Drug Design and Pharmacology, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, Københavns Universitet2 unknown3 Kurser, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Københavns Universitet4 Drug Research Academy B, Drug Research Academy, Faculty of Pharmaceutical Sciences, Københavns Universitet5 Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet6 Kurser, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Københavns Universitet7 Drug Research Academy B, Drug Research Academy, Faculty of Pharmaceutical Sciences, Københavns Universitet8 Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
IP-10 release assay on filter paper
Interferon-γ release assays (IGRA) are probably the most accurate tests for detection of latent M.tuberculosis infection, but IGRAs are labour intensive and transport of samples over longer distances is difficult. IP-10 is expressed at 100-fold higher levels than IFN-γ, and IP-10 release assays have comparable performance to IGRA. The aim of this study was to explore the diagnostic potential of a novel IP-10 release assay based on dried plasma spots (DPS).IP-10 and IFN-γ was determined in plasma and in DPS by ELISA. Diagnostic algorithms for IP-10 plasma and DPS tests were developed on a training cohort comprising 60 TB patients and 59 controls. The diagnostic accuracy was assessed in a validation cohort comprising 78 TB patients and 98 healthy controls. Plasma was measured in Spain and DPS samples were sent to Denmark with conventional postal service for analysis.IP-10 was readily detectable in both plasma and DPS, and correlation was excellent (r(2)=0.95). QuantiFERON Gold-In-Tube (QFT-TB) and IP-10 in DPS and plasma rendered comparable sensitivity (78;82;84%), specificity (100;97;97%) and indeterminate rates (p>0.55).The DPS based IP-10 test has comparable diagnostic accuracy as the QFT-TB and samples can be sent with conventional mail over long distances for analysis without affecting the results.
European Respiratory Journal, 2013, Vol 42, Issue 2, p. 495-503