Department

Microbiology

Preferred Sample Type

HIV 1 genotypic resistance testing (protease and reverse transcriptase region)

Suitable Specimen Types

EDTA Whole Blood
CSF

2 ml of Plasma/CSF ideally with V.L. >500 cp/ml.

Sample Preparation

Please note that we will attempt to amplify the
virus if less than 500 cp/ml (must be above 40 cp/ml)

Turnaround Time

14 days

HIV 1 genotypic resistance testing (protease and reverse transcriptase region)

General Information

Genotypic HIV-1 resistance testing is the current recommended method for determining drug resistance in HIV infection. Genotypic resistance data provides information on the presence/absence of drug resistance mutations, which is used as a predictor of virological response to therapy. This aids clinical decisions regarding therapy changes. Choosing the most appropriate therapy regime improves patient management and reduces the cost of care.

The methodology for genotypic HIV-1 resistance testing involves extraction of RNA, reverse transcription of RNA to DNA in a one-step RT-PCR and nested PCR amplification, population sequencing and sequence analysis

Sample Stability

Freshly drawn specimens (whole blood) may be held at 2 to 30°C for up to 6 hours prior to centrifugation. Plasma and CSF samples are stored for 2 years at -20°C.

Patient Preparation

For taking blood or CSF samples we recommend that users follow either their local protocols or “The Royal Marsden Manual of Clinical Nursing Procedures”.

Lavender top blood (EDTA) sample

Sufficient blood for the test should be drawn into lavender topped (EDTA) vacuum tubes
Invert tube 8–10 times.

The HIV 1 genotypic resistance testing request form is available from the following link HIV-1 RESISTANCE TESTING REQUEST FORM

CSF samples

Undiluted CSF sample should be sent in a sterile universal container.

Request forms

Please ensure as much clinical information as possible is provided on the request form.

Notes

HIV viral load samples with viral loads greater than 500 copies/ml are kept indefinitely so that retrospective resistance testing can be performed.

Specifications

EQA Scheme?: Yes
EQA Status: QCMD and HIV Antiviral Sequencing Panel- Sequencing group, PHE Colindale