Human Immunodeficiency Virus 1 (HIV-1) PhenoSense Entry® (Monogram® Fuzeon Resistance)

CPT Code(s):


Collection Procedure:

  • Collect specimens in two lavender-top tube (EDTA) or two PPT tubes. Do not use green-top tubes (heparin).
  • Centrifuge specimens within six hours of collection.
  • Transfer the collected plasma to one or more polypropylene screw-capped tubes and freeze it.
  • Ship specimens frozen. To avoid delays in turnaround time, when requesting multiple tests on frozen samples, submit separate frozen specimens for each test requested.

Specimen Requirements:

Type: Plasma, frozen
Container/Tube: Lavender-top tube (EDTA) or plasma-preparation tube (PPT)

Sample Volume: 3 mL

Minimum Volume: 1.1 mL

Storage: Freeze specimens immediately after collection.
Rejection Criteria:

  • Insufficient volume
  • Heparinized plasma
  • Non-frozen specimens
  • PPT not centrifuged


This test is used to determine a patient’s phenotypic susceptibility to enfuvirtide (Fuzeon®) and assesses likely effectiveness before enfuvirtide is added to that person’s regimen or before changing a regimen that includes enfuvirtide.


This procedure should be used for patients with documented HIV-1 infection and viral loads ≥ 1,000 copies/mL.


Polymerase chain reaction (PCR) amplification and viral culture