HIV - 1 Drug Resistance Asaay (PI)

The HIV drug resistance test detects viral changes that reduce effectiveness of antiretroviral medicines. Performed on a blood sample, genotypic testing identifies specific resistance mutations in the virus’s genes; phenotypic testing measures drug susceptibility. Tests are recommended before starting or changing therapy and when viral load rises despite treatment. Results guide selection of effective drugs to optimize or switch regimens.

HIV‑1 genotype "not detected" means the lab did not find known resistance mutations in the genes tested. That may indicate a true wild‑type virus or a viral load too low for reliable genotyping. It does not mean the infection is cured. Continue prescribed antiretroviral therapy and regular viral‑load monitoring; repeat resistance testing if viremia rises or treatment appears to fail.

Perform genotypic HIV drug‑resistance testing at baseline (at diagnosis or before starting antiretroviral therapy) and whenever virologic failure is confirmed (typically ≥200 copies/mL). For reliable amplification, viraemia is ideally >500 copies/mL; proviral DNA testing may be used if viral load is suppressed. Include reverse transcriptase, protease and integrase regions; test urgently in pregnancy and before changing regimens after failure.

The HIV resistance gene test detects human genetic variants—most commonly the CCR5-Δ32 mutation—that reduce HIV’s ability to enter immune cells. It’s performed on blood or saliva and used in research, ancestry or clinical counseling. A positive result may lower infection risk but does not guarantee immunity and doesn’t replace regular HIV testing, prevention or medical advice.

HIV drug resistance occurs but is not universally common. Transmitted resistance is low-to-moderate—about 5–15% in some regions—while acquired resistance has fallen where potent combination therapy, viral‑load monitoring, and adherence support are used. Risk rises with inconsistent adherence, prior antiretroviral exposure, or suboptimal regimens. Resistance testing before starting treatment and if viral load rebounds helps guide effective therapy.

An HIV assay is a laboratory test that detects HIV infection by measuring viral components or the body’s immune response. Types include antibody tests (ELISA/rapid), fourth‑generation antigen/antibody assays that also detect p24 antigen, and nucleic acid tests (PCR/NAT) that find HIV RNA for early diagnosis and viral‑load monitoring. Positive screens need confirmatory testing.