What is being tested?In genotypic resistance testing, the genetic code of the particular strain of
HIV you have been infected with is checked to see if there are any genetic
mutations or changes that are known to cause drug resistance. HIV is resistant to an antiviral medication if it keeps multiplying while a person is taking the drug. Changes (mutations) in the
virus cause resistance. HIV mutates almost every time a new copy is made, but not every mutations causes resistance. Antiviral drugs control most types of HIV. However, a mutation that is resistant to a drug will multiply and become the most common form of the virus in the body. This is called “selective pressure” because the drug “selects” versions of the virus that are resistant to it. For certain drugs, single mutations of the gene increase resistance to high levels. For other drugs, there are several mutations that are associated with resistance.
