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HIV Tropism Blood Test (Genotypic Resistance Profile)

Published: August 9, 2026Updated: August 16, 2026

This test analyzes the genetic makeup of your HIV virus to determine which specific viral proteins it relies on for replication. It helps guide treatment choices by identifying resistance patterns.

Quick summary

["Understanding your HIV virus’s tropism can help tailor your treatment to be most effective."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
53923-9
Short code
HIV1 tropism Bld
Synonyms
HIV1 tropism Bld
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86701
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Does the Test Measure?

The test looks for specific viral genes (e.g., **gp120**, **gp41**, or **Vpr**) that indicate how the virus attaches to and enters immune cells. These genes are part of the virus’s ‘tropism’—its preference for certain cell types. Results are reported as a combination of viral genes detected, not specific percentages.

Why Might You Need This Test?

Your healthcare provider may recommend this test if you’re starting HIV treatment, experiencing treatment resistance, or have a virus that hasn’t responded well to standard therapies. It helps ensure your treatment targets the right viral proteins to maximize effectiveness.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is processed to extract viral genetic material (RNA or DNA) and analyzed using advanced laboratory techniques (often **next-generation sequencing**) to identify specific viral genes.

What Are the Results?

Results are typically reported as a list of viral genes detected (e.g., **gp120+**, **gp41+**, **Vpr+**) or a summary of resistance patterns. No numeric ranges are provided because the test focuses on qualitative detection rather than absolute concentrations.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: How This Test Impacts Treatment

Short name

HIV Tropism Test

Frequently asked questions

How Does the Test Help My Treatment?
If certain viral genes are identified, your treatment may be adjusted to include drugs that target those specific proteins. For example, if the virus relies heavily on **gp41**, a fusion inhibitor (like enfuvirtide) might be added to your regimen. This approach can improve viral suppression and reduce drug resistance over time.
What If My Test Shows Resistance to Common Drugs?
If your test reveals resistance to standard HIV medications, your healthcare provider may recommend alternative therapies or monitor your response more closely. Resistance patterns can evolve, so retesting may be needed as your treatment progresses.
How Often Should I Get This Test?
Your provider will determine frequency based on your treatment history, viral load, and response to therapy. Typically, it’s done at the start of treatment or if there’s suspicion of resistance, but not as a routine check.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy