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Evaluation of a sensitive/less sensitive testing algorithm using
the bioMerieux Vironostika-LS assay for detecting recent HIV-1 subtype
B' or E infection in Thailand.
AIDS Research and Human Retroviruses 2003;19(6):481-486.
Young CL, Hu DJ, Byers R, Vanichseni S, Young NL, Nelson R, Mock PA,
Choopanya K, Janssen R, Mastro TD, Mei JV.
Abstract
The performance of the bioMerieux Vironostika-LS EIA (less sensitive enzyme
immunoassay) was assessed to detect recent seroconversion among injecting
drug users (IDUs) in Bangkok, Thailand who were infected with either HIV-1
subtypes B' or E (also known as circulating recombinant form CRF01_AE). To
evaluate the Vironostika-LS EIA in non-B subtypes, we collected longitudinal
specimens (n = 796) from 115 IDUs (subtype B' infection, n = 24; subtype
E infection, n = 91). After testing HIV-positive specimens with the Vironostika-LS
EIA, standardized optical densities (SODs) were calculated using median values
to determine the window period, which is the time from seroconversion on
a standard EIA to seroconversion on the Vironostika-LS EIA for a given SOD,
for either subtype. For an SOD cutoff of 1.0, Vironostika-LS EIA results
showed a mean window period of 239 days (95% confidence interval [95% CI],
208-287 days) for subtype B' and 356 days (95% CI, 318-402 days) for subtype
E in Thailand. This outcome demonstrates that the Vironostika-LS EIA has
significantly different performance characteristics in detecting recent seroconversion
between different HIV-1 subtypes. Accurate identification of recent infection
and estimation of incidence for HIV-1 strains other than North American subtype
B, using the Vironostika-LS EIA, requires knowledge of specimen subtype and
use of appropriate cutoffs and mean window periods.