Glossary

clinical cut-off (CCO) – a test result that is associated with an impact on clinical care. With resistance tests a lower CCO is the level below which a drug is still sensitive or active. This is often set at a 20% loss of activity (compared to wild-type HIV). An upper CCO is the level above which the drug is not considered active (ie resistant). This is often set at an 80% loss of activity (compared to wild-type HIV).

intent-to-treat analysis (ITT) and on-treatment analysis (OT) – two important ways that trial results are analysed. ITT includes all patients who entered the study and is more rigorous. OT only calculates the response rates for people still on the randomised treatment.

informed consent – a document that every person who participates in research is required to sign before entering the study. It outlines the details of a the study, including the known risks and benefits or any intervention. It also explains what is required during the study in terms of additional tests and clinic visits.

baseline – baseline refers to the start of any period being studied. For someone who is HIV positive, their baseline CD4 and viral load counts are the first tests they ever had taken. For someone entering a study, the baseline results refer to their test results at the start of the study. Baseline results for following resistance refers to the results of the first resistance test.

transmission of HIV – see HIV transmission