If the sample grows more than normal, it is resistant to the medication. It can take over a month to get the results. However, a new test from ViroLogics takes about two weeks. Genotypic Testing For genotypic testing, the genetic code of HIV is compared to the wild type. The code is a long chain of molecules called nucleotides.
Results come back in about two weeks.
Sometimes a mutant version of HIV can resist more than one antiviral medication. This means that indinavir and ritonavir are cross-resistant. Cross-resistance is important when you change your antiviral medications. If your virus is already resistant to certain drugs, you should choose new drugs that are not cross-resistant. We do not totally understand cross-resistance in current antiviral medications.