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Human Immunodeficiency Virus (HIV) Genotypic Resistance Testing

Last updated May 18, 2018

Human Immunodeficiency Virus Genotypic Resistance Testing evaluates the strain of HIV with which an individual is infected, to determine whether or not it has developed resistance to antiretroviral drug therapy.


What are the other Names for this Test? (Equivalent Terms)

  • Anti-Retroviral Drug Resistance Blood Testing
  • ARV Drug Resistance Blood Testing
  • HIV Genotypic Resistance Blood Testing 

What is Human Immunodeficiency Virus (HIV) Genotypic Resistance Testing? (Background Information)

  • Human immunodeficiency virus (HIV) is a retrovirus responsible for causing acquired immunodeficiency syndrome (AIDS). The virus mutates frequently, and can develop resistance to drug therapy
  • HIV is transmitted through bodily fluids, especially blood and sexual secretions. It can also be transmitted from a mother to the fetus, in the womb
  • HIV infects a specific type of white blood cell, called a CD4 T lymphocyte, or helper T cell. The virus resides in these cells and with time, can drastically lower their numbers
  • Modern methods to combat an HIV infection involve the use of antibiotics, called antiretroviral (ARV) drugs. ARV drugs target various points in the viral replication cycle in an attempt to disrupt its replication
  • However, viruses such as HIV do not contain genetic proofreading mechanisms. This leads to frequent mutations in the viral genetic code, as it replicates, creating offspring that evade recognition by ARV drugs. In this way, microorganisms, such as human immunodeficiency virus, develop resistance to antiretroviral drugs
  • Human Immunodeficiency Virus Genotypic Resistance Testing evaluates the strain of HIV with which an individual is infected, to determine whether or not it has developed resistance to antiretroviral drug therapy 

What are the Clinical Indications for performing the Human Immunodeficiency Virus (HIV) Genotypic Resistance Testing?

The clinical indications for performing a HIV Genotypic Resistance Blood Testing include evaluating the antiretroviral (ARV) drug resistance potential of a strain of HIV:

  • Prior to the start of ARV therapy, to help guide treatment
  • After the start of ARV therapy, to determine whether or not the strain has developed resistance
  • When ARV therapy is not effective 

How is the Specimen Collected for Human Immunodeficiency Virus (HIV) Genotypic Resistance Testing?

Following is the specimen collection process for Human Immunodeficiency Virus Genotypic Resistance Testing:

Sample required: Blood

Process: Insertion of a needle into an arm vein.

Preparation required: No special preparation is needed prior to the test. 

What is the Significance of the Human Immunodeficiency Virus (HIV) Genotypic Resistance Testing Result?

Antiretroviral (ARV) drug resistance genes uncovered by HIV Genotypic Resistance Blood Test may indicate that ARV therapy must be modified, to provide a therapeutic effect. 

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario. 

Additional and Relevant Useful Information:

  • There are two types of HIV: HIV-1 is more prevalent in the world, whereas HIV-2 is more prevalent in Africa, especially West Africa. Generally, when HIV infection is mentioned, it means an HIV type-1 infection, since HIV type-2 is much rarer
  • Various additional tests are combined to establish a diagnosis of HIV, such as a p24 antigen blood test
  • A CD4 and CD8 test is done to help in the diagnosis of AIDS
  • In order for this test to be effective, there must be sufficient HIV copies to provide adequate testing material; specifically, the viral load must be greater than 500 copies/mL 

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

References and Information Sources used for the Article:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Aug. 1, 2014
Last updated: May 18, 2018