Glossary

genotype test – a test that looks at how the genetic structure of a sample of HIV and whether the virus has changed with drug resistant mutations.

fold-change – a term relating to drug resistance after a phenotype resistance test.

4-fold resistance (also called a 4-fold loss in sensitivity) means you need to use four times the dose to get the same reduction in viral load.

DEXA – a non-invasive scan that can measure the percentage of different body areas (whole body, trunk, right leg etc) that are muscle or fat. DEXA scans cannot determine if this is central fat (visceral adipose tissue, VAT) or sub-cutaneous fat (under the skin).

DEXA scan also can measure bone density and is used to monitor risk of osteopenia and osteoporosis.

blip – small, occasional increase in viral load.

viral rebound – when your viral load has been undetectable (under 50 copies/mL) and then becomes detectable. Sometimes viral rebound can be a lab error, sometimes a small temporary blip, and sometimes a real rebound that shows your virus may have developed resistance to one or more of the drugs in a combination treatment. See: virological failure.