The growth rate of the HIV is compared to the rate of wild type virus. 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. 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.