Infection with human immunodeficiency virus type 1 (HIV-1) is followed by a period of clinical latency wherein decreases in CD4+ cells may be minimal for prolonged periods. Progression to symptomatic acquired immunodeficiency syndrome (AIDS) causes CD4+ T-cell counts to decrease. Therefore, the CD4+ assay has become the surrogate for monitoring disease progression and initiating therapy. This count, however, is an imperfect marker of disease progression.

Assays that measure levels of HIV-1 ribonucleic acid (RNA) in plasma for use in managing HIV-1 disease have recently become available. In general, detection and quantification of viral particles involve the target, i.e., HIV RNA, and the use of a signal, typically a complementary strand of nucleic acids, which is labeled so that the resulting complex can be detected and quantified. Since the HIV RNA exists in such small quantities, the resulting complex must be amplified in some way to enable detection. Two basic strategies have been used. In the Amplicor® technique (Roche Molecular System), polymerase chain reaction (PCR) is used to amplify the target HIV RNA. In contrast, in the Quantiplex® technique (Chiron Corporation), the signal is amplified, allowing detection of the HIV RNA in its original physiologic concentration.

Plasma HIV-1 RNA quantification is considered medically necessary for use in monitoring disease progression in HIV-infected individuals.

Plasma HIV-1 RNA quantification is considered medically necessary for monitoring response to antiretroviral therapy.

Plasma HIV-1 RNA quantification is considered investigational for predicting maternal-fetal transmission of HIV-1.

Suggested frequency for HIV RNA measurement is as follows:

• At baseline: 2 measurements, 2 to 4 weeks apart;
• Every 3 to 4 months or in conjunction with CD4+ counts;
• Shorter intervals, as critical decision points are neared;
• Three to 4 weeks after initiating/changing therapy.

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One plasma HIV-1 RNA assay has received approval from the FDA for monitoring disease progression (Amplicor® HIV-1 Monitor HIV-1 plasma RNA quantification test manufactured by Roche Molecular System, Inc., Alameda, Calif.). The approval language also acknowledged ongoing evaluation of the use of this assay in monitoring response to antiretroviral therapy. Approval of the Quantiplex® HIV-RNA assay, manufactured by Chiron Corporation, is expected shortly. Other commercial and in-house methods have been described in technical publications and clinical studies.

In 1998, two new CPT codes were introduced to describe viral load testing: CPT code 87535 (HIV-1 amplified probe technique) and 87536 (HIV-1 quantification). Prior to 1998 a series of CPT codes were used to describe the individual steps in the testing process. The CPT codes differed slightly, depending on whether the Amplicor® or Quantiplex® process was used. The codes are summarized as follows:

Branched DNA signal amplification technology (Quantiplex®, manufactured by Chiron Corporation)
 
83890: Nuclear molecular diagnostics; molecular isolation or extraction, each nucleic acid type (ie. DNA or RNA)
 
83896: Nuclear molecular diagnostics; nucleic acid probe, each (typically 2 are used)
 
83898: Nuclear molecular diagnostics; nucleic acid probe with amplification
 
82397: Chemiluminescent assay
 
83912: Nuclear molecular diagnostics; interpretation and report

Polymerase chain reaction (PCR) technology (Amplicor®, manufactured by Roche Molecular Systems):
 
83890: Nuclear molecular diagnostics; molecular isolation or extraction, each nucleic acid type (ie. DNA or RNA)
 
83898: Nuclear molecular diagnostics; nucleic acid probe with amplification, e.g., PCR (typically 7 are used)
 
83912: Nuclear molecular diagnostics; interpretation and report

A search of the literature was completed through the AIDSLINE database for the period of January 1980 through August 1996. The search strategy focused on references containing the following Medical Subject Headings:

– ACT and HIV-1
 
– HIV-1 and RNA and Viral Load
 
– Human Immunodeficiency Virus
 
– Polymerase Chain Reaction
 
– Reverse Transcriptase
 
– RNA and Virus

See Also:

TEC Assessments: 1996, Tab 25
 
For policy guidelines, see (Saag MS, Holodniy M, Kuritzkes DR. HIV viral load markers in clinical practice. Nature Med 1996;2(6):625-29).

HIV-1 Infection, Plasma HIV-1 RNA Quantification
Plasma HIV-1 RNA Quantification for HIV-1 Infection
Viral load, HIV