AEGiS-13IAC: Comparative analysis of HIV-1 viral load assays on sub-type quantification: Bayer bDNA version 3.0 versus Roche Amplicor Monitor version 1.5.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

Comparative analysis of HIV-1 viral load assays on sub-type quantification: Bayer bDNA version 3.0 versus Roche Amplicor Monitor version 1.5.

Int Conf AIDS 2000 Jul 9-14; 13:36 (abstract no.. LbPeA7017)

Elbeik T, de Souza M, Sriplienchan S, Trichavaroj R, Chuenchitra C, Nassos P, Ng VL
University of California, San Francisco, San Francisco General Hospital, 94110. Fax: 415-206-3045, E-mail: elbeik@its a.ucsf.edu.

BACKGROUND: Two commercially available HIV viral load assays (Bayer bDNA, v. 3.0,'bDNA'; Roche Amplicor Monitor, v. 1.5,'Ampticor') detect all reference isolates within group M (subtypes A, B, C, D and E) at a single concentration of 4.4 logl0 virus particles/mL.

OBJECTIVE: 1) To compare precision and absolute values between assays for samples containing 1.7-4.4 logl0 virus particles/mL of different group M isolates (Walter Reed Subtype panel), and 2) to compare absolute HIV viral load values in subtypes B and E patient samples.

METHOD: Subtypes of known concentration (Walter Reed Subtype panel) were diluted in normal human plasma to yield multiple samples, each containing 4.4, 3.7, 3, 2.7, 2.3 and 1.6 log₁₀ virus particles/mL, and tested with each assay. (For Amplicor, two sample extraction methods were used - ultra-sensitive for all samples, and the standard for only those samples containing 4.4 log₁₀ virus particles/mL). 106 and 85 patient specimens containing either subtypes B or E were tested with each assay.

RESULTS: On average, Amplicor yielded values approximately 0.33 log₁₀ higher than bDNA. Standard deviations ranged from 0.03-0.05 logl0 (bDNA) and 0.14-0.17 log₁₀ (Amplicor). bDNA demonstrated a linear relationship with virus concentration for all subtypes, whereas Amplicor demonstrated such for only subtypes A, B and D. The Amplicor standard extraction method yielded values approximately 0.4 log₁₀ higher than the ultra-sensitive extraction method. Although Amplicor and bDNA yielded comparable results for the 106 patient specimens containing subtype B, Amplicor yielded values - 0.25 log₁₀ higher than bDNA for patient specimens containing subtype E, with significant discrepancies at both high and low HIV viral load values.

CONCLUSION: Both assays detected all HIV group M subtypes at multiple concentrations, but bDNA yielded more precise values than Amplicor. Absolute values for subtypes C and E were significantly discrepant at both low and high HIV viral load values.

Keywords: AEGIS, Viral Load, HIV-1, HIV Infections, Virion, Human, complications, AIDS
000709
LbPeA7017