Web resources for HIV-1 genotypic-resistance test interpretation

An article in the 15 April issue of Clinical Infectious Diseases, by Tommy Lui from US Division of Infectious Diseases, and and Robert Shafer from Stanford University, usefully describes the scientific principles of HIV-1 genotypic-resistance test interpretation and the most commonly used Web-based resources for clinicians ordering genotypic drug-resistance tests.

Prospective controlled studies have shown that patients whose physicians have access to drug-resistance data, particularly genotypic-resistance data, respond better to therapy than control patients of physicians without such access.

However, interpreting the results of HIV-1 genotypic drug-resistance tests is one of the most difficult tasks facing clinicians caring for HIV-1-infected patients because of the complex interactions among the many mutations that contribute to drug resistance; the varying levels of reduced susceptibility caused by these mutations; and the inability of drug-resistance tests to detect minor, yet clinically relevant, drug-resistant variants in a patient’s virus quasispecies.

Web sites providing HIV-1 resistance summaries

International AIDS Society, USA

Expert summary of the most clinically relevant mutations.

HIV Sequence Database, Los Alamos National Laboratories

Summary of nearly all HIV-1 mutations associated with in vitro or in vivo drug resistance.

Searchable form of Los Alamos summary.

Stanford University HIV Drug Resistance Database

Graphical summaries of PI, NRTI and NNRTI drug-resistance mutations, respectively.

Antiretroviral drug summaries by drug.

Drug-resistance mutation phenotypic data.

Summary of published studies linking baseline genotype and virologic response to a new treatment regimen.


Liu TF, Shafer RW. Web resources for HIV-1 genotypic-resistance test interpretation. Clinical Infectious Diseases 2006;42:1608-1618.

Links to other websites are current at date of posting but not maintained.