COVILL S, MATHIS J, HODGE P, CASS M, BOTT M, BODRUG S; Interscience Conference on Antimicrobial Agents and Chemotherapy (41st : 2001 : Chicago, Ill.).

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2001 Dec 16-19; 41: abstract no. H-755.

Gen-Probe Incorporated, San Diego, CA

BACKGROUND: Quantification of HCV RNA can be used to measure viral load for making and modifying treatment decisions. Commercially available quantitative assays have a limit of detection of 500-600 IU/mL. A more sensitive quantitative assay has the potential to provide better information for treatment decisions. The sensitive qualitative HCV TMA assay developed by Gen-Probe was modified to create a quantitative assay. METHODS: Through the use of an external calibration curve and the addition of a quantitative Pseudo-Target Reagent (PsT) and Probe Reagent, the qualitative HCV TMA assay was converted to a quantitative assay. Sensitivity, linearity and reproducibility were assessed by testing a serially diluted HCV positive sample by multiple operators, across multiple days, using multiple lots of reagents. Varying the level of PsT permitted variations to the dynamic range of the assay. RESULTS: The sensitivity of the assay was 100% at 50 IU/mL, and the percent recovery of the controls was on average within 20% (0.1 log[10]) of the expected value. The inter-assay %CV was on average 10-15% within the tested range of 50 to 4,000 IU/mL. The log[10] measured concentration of virus was compared to the log[10] expected concentration to evaluate linearity. The regression line yielded an R[2] value of 0.991 and a slope of 0.7. The linear range of the assay was confirmed to be 20 to 4,000 IU/mL. The sensitivity and dynamic range was adjusted by adjusting the level of PsT. Decreasing the amount of PsT by 10-fold increased the low end sensitivity of the assay by approximately 10-fold, whereas increasing the amount of PsT by 10-fold shifted the range of the assay to allow better interpolation of higher level samples. CONCLUSION: The data demonstrate that the quantitative HCV TMA assay yields sensitive, reproducible, and accurate results across the dynamic range of 20 to 4,000 IU/mL, and the dynamic range can be altered by varying the levels of Pseudo-Target Reagent.

Publication Types:

• Meeting Abstracts

Keywords:

• Biological Assay
• Calibration
• Hepacivirus
• Indicators and Reagents
• Sensitivity and Specificity
• Viral Load

Other ID:

• GWAIDS0029648

UI: 102269280

From Meeting Abstracts