Evaluation of a rapid, point-of-care test device for the diagnosis of hepatitis C infection.

BACKGROUND: Despite considerable evolution in the quality of laboratory-based testing for detection of HCV, the availability of rapid, point-of-care tests may increase diagnoses by increasing opportunities for testing outside of traditional laboratory settings. OBJECTIVES: We evaluated the performance of a new, rapid HCV test that can be used with venous blood, finger stick blood, serum, plasma, or oral fluid and compared it to FDA-approved laboratory methods. STUDY DESIGN: HCV positive subjects as well as subjects at low risk for HCV were tested with the rapid test using all 5 specimen types and results compared to FDA-approved laboratory methods. In addition, performance was assessed in commercially available seroconversion panels. RESULTS: Sensitivity and specificity of the rapid test was equivalent to laboratory EIA and performance was comparable across all 5 specimen types. CONCLUSIONS: The OraQuick HCV Rapid Antibody Test appears suitable as an aid in the diagnosis of HCV infection.

The discrimination of IgM and IgG type antibodies and Fab' and F(ab)2 antibody fragments on an industrial substrate using scanning force microscopy.

We have previously employed scanning force microscopy (SFM) to study antibody-antigen molecular interactions on microtiter wells used for enzyme linked immunosorbant assays (ELISA). Here we demonstrate the ability of SFM to image and discriminate different types of antibody and antibody fragments bound to an ELISA well surface. The samples studied include a type IgG antibody with a proportion of bound IgM and two-dimensional films of whole IgG antibody, and Fab' and F(ab)2 antibody fragments. Molecular resolution is achieved in each case despite the size of substrate features exceeding most of the molecular dimensions observed. Analysis of the data shows that the SFM overestimates molecular dimensions by an approximately constant amount, which is proposed to principally result from the effects of a finite probe size and not from deformation of the molecular species due to the imaging forces employed.