HIV-1/-2 Ab Differentiation (Supplemental Use Only) with Reflex HIV 1 RNA

Message

Used to confirm results on reactive HIV antigen and antibody testing.

Quest Code
93170

Test Code

HVDIP

Includes

If HIV-1/2 Antibody Differentiation is Indeterminate or Negative, then HIV-1 RNA, Qualitative Real-Time PCR will be performed at an additional charge (CPT code(s): 87535).

Preferred Specimen

3 mL Plasma collected in: EDTA (lavender-top) tube

Minimum Volume

2 mL

Other Acceptable Specimens

Serum collected in: Red-top tube (no gel) • Plasma collected in: EDTA (lavender-top) tube

Instructions

Serum: Collect in a serum separator tube or red-top tube (no gel). The tube should be centrifuged after clotting. Spun serum separator tubes may be submitted at room temperature or refrigerated unopened without transfer to a plastic, screw-cap vial. Red-top tube (no gel) serum should be transferred to a plastic, screw-cap vial and submitted for testing.

Plasma: Collect in an EDTA (lavender-top) tube and centrifuge tube within 24 hours of collection. Transfer plasma to a plastic, screw-cap vial, label as plasma, and submit for testing.

Submitted tubes must be labeled with patient identifier and submitted only for HIV testing.

Transport Container

Transfer Container

Transport Temperature

Frozen

Specimen Stability

Room temperature: 72 hours

Refrigerated: 5 days

Frozen: 30 days

Clinical Significance

This test is used to help diagnose HIV-1 and HIV-2 infection, including acute infection, and to differentiate HIV-1 from HIV-2. It is consistent with the HIV diagnostic algorithm proposed by the Centers for Disease Control and Prevention [2]. It can be used in adults, including pregnant women, and in children at least 2 years old.

This test allows detection of acute HIV-1 infection based on the presence of p24 antigen, before seroconversion occurs, allowing for earlier diagnosis than with previous tests. It can also detect HIV-1 and HIV-2 post-seroconversion, based on antibodies. If the HIV-1/HIV-2 antigen/antibody test is positive, an antibody-based HIV-1/HIV-2 test is done (at additional charge) to confirm infection and identify whether it is caused by HIV-1 or HIV-2. However, the HIV-1/HIV-2 differentiation test will be negative during acute infection (prior to development of specific antibodies). If the antibody-based HIV-1/HIV-2 test is negative, the blood specimen will be reflex-tested for the presence of HIV-1 RNA (at additional charge) to identify patients with acute HIV-1 infection [1].

The United States Preventive Services Task Force (USPSTF) recommends HIV screening for all pregnant women, and for individuals between 15 and 65 years of age who live in regions with an HIV prevalence of >0.1% [2]. In addition, antigen/antibody-based HIV testing is recommended for high-risk individuals who want to begin pre-exposure prophylaxis (PrEP) therapy, because HIV-positive patients who start PrEP without knowing their HIV status face an elevated risk of antiretroviral resistance [3,4].

Because 40% of new HIV infections are transmitted unknowingly by people unaware of their HIV status, early diagnosis is important to reduce HIV transmission [5]. Antigen/antibody-based HIV screening assays have >99.7% sensitivity and >99.3% specificity for HIV infection and can identify most (>80%) acute infections that would otherwise require nucleic acid testing for detection [6,7].

Performing Laboratory
Performing Laboratory

Quest Diagnostics-Pittsburgh Lab

875 Greentree Road

Pittsburgh, PA 15220-3508

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.