Resistance Testing Recommendations

The following clinical areas of need have been identified by the International AIDS Society – USA Panel (IAS/USA):

Summary of Clinical Situations in which Resistance Testing is Recommended

Acute or Recent HIV Infection	Before Initiation of Antiretroviral Therapy in Established HIV Infection^b
Acute infection^a	Patients infected within previous 2 years and possibly longer
HIV infection within previous 12 months (if known)	First regimen failure
Suboptimal HIV-1 RNA response to therapy	Multiple regimen failure
Pregnancy if mother has detectable plasma HIV-1 RNA level

^{a: Therapy should not be delayed for resistance testing results.

b: In untreated, established infection, wild type isolates may replace drug resistant quasi species over time.}

The European Resistance Testing Recommendations published in AIDS suggest the following clinical indications:

Clinical Characteristics	Recommendation
Treatment naïve patients, (primary Infection/recent infection)	Consider testing (not used in the previous table) Test for resistance if reasons to suspect transmission from a treated individual exist and treatment is to be initiated.
Chronic infection	Consider testing for resistance if transmission rate is high or reasons to suspect transmission from treated individual exist.
Post-Exposure Prophylaxis	Do not delay treatment due to resistance testing, but if sample from the index case is available, test and treat accordingly.
Treated Patients	Test for resistance in all cases where changes
Pregnancy	Test for resistance if the mother has a detectable virus load.
Pediatrics*	Test for resistance in HIV-1 infected children born to mothers on treatment with detectable viremia and consider testing in children with virologic treatment failure.