HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes
Quest Diagnostics
Sample type: Serum
Requires fasting: No
Phlebotomy required
Details
HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes - This algorithm 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 recommended by the Centers for Disease Control and Prevention. It can be used in adults, including pregnant women, and in children 2 years or older.
Reflex testing uses predefined clinical logic to automatically order one or more follow-up tests based on the initial test results. Reflex tests are performed automatically without the intervention of the ordering practitioner. They are conducted using the same sample your Patient already provided. If reflex tests are required, there will be additional charges.
Initial test
- HIV 1+2 Ab+HIV1 p24 Ag
Possible reflex biomarkers
- HIV-1 Ab
- HIV-2 Ab
- HIV 1 RNA
- HIV 2 RNA
Estimated days for results: Results should be available in 2 - 5 business days after the sample is collected
HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes - This algorithm 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 recommended by the Centers for Disease Control and Prevention [2]. It can be used in adults, including pregnant women, and in children 2 years or older.
This panel begins with an antigen/antibody assay that allows for detection of acute HIV-1 infection based on the presence of p24 antigen before seroconversion occurs, and HIV-1 and HIV-2 antibodies post-seroconversion. If the HIV-1/HIV-2 antigen/antibody test is positive, an antibody-differentiation test is done (at additional charge) to confirm infection and identify the presence of HIV-1 or HIV-2 specific antibodies. However, the HIV-1/HIV-2 differentiation test can be negative during acute infection (prior to development of specific antibodies). If the antibody-based HIV-1/HIV-2 supplemental test is negative, the specimen will be reflexed to the HIV-1 and HIV-2 RNA, Qualitative, Real-Time PCR test (at additional charge), which can detect the presence of HIV-1 and 2 RNA and identify patients with acute HIV-1 or 2 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].
References- Moyer V, USPTF. Ann Intern Med. 2013;159:51-60.
- CDC. Clinical Testing Guidance for HIV. Clinical Testing Guidance for HIV | HIV Nexus | CDC. Published September 10, 2024. Accessed January 27, 2025.
- CDC. Preventing HIV with PrEP. https://www.cdc.gov/hiv/prevention/prep.html?CDC_AAref_Val=https://www.cdc.gov/hiv/basics/prep.html. Published January 18, 2024. Accessed January 27, 2025.
- Livant E, et al. J Clin Virol. 2017;94:15-21.
- CDC. HIV testing. https://www.cdc.gov/hiv/testing/index.html. Published March 2019. Accessed May 20, 2019.
- Nasrullah M, et al. AIDS. 2013;27:731-737.
- Chavez P, et al. J Clin Virol. 2011;52(Suppl 1):S51-S55.
2–5 business days
Blood Draw Options with Fullscript
Fullscript offers several convenient phlebotomy options to complete your lab testing:
Quest Diagnostics Patient Service Centers (PSC)
- Location: Visit a nearby Quest Diagnostics Patient Service Center.
- Cost: $10 sample collection fee (paid during lab order checkout).
- Scheduling: Schedule your appointment here. Appointments are recommended to reduce wait times. Walk-ins are accepted, but may experience delays. Aim to arrive 10 minutes before your appointment.
- Collection Instructions:
- Bring a valid ID.
- Bring your digital or printed requisition form, available in the Labs tab of your Fullscript account.
- Check-in: Scan the QR code from your confirmation email or follow kiosk instructions.
- More Info: Quest Diagnostics blood draw guide
Getlabs Mobile Phlebotomy
- Location: Sample collection at your home or office.
- Cost: $85 sample collection fee (paid during lab order checkout).
- Availability: Available in most locations – enter your ZIP code during checkout to confirm.
- Scheduling: Schedule your appointment here through your Fullscript account.
- Collection Instructions:
- Have your digital or printed requisition form and valid ID ready.
- Your phlebotomist will contact you by phone to coordinate arrival.
- More Info: Getlabs blood draw guide
- Preferred Specimen(s): 3 mL serum
- Alternative: NA
- Minimum Volume: 2 mL
- Collection Instructions: NA
- Transport Container: Serum separator tube (SST)
- Transport Temperature: Room Temperature
- Specimen Stability:
- Room temperature: 72 hours
- Refrigerated: 5 days
- Frozen: 30 days
- Reject Criteria:
- Gross hemolysis • Frozen serum separator tube (SST)
Minimum age:
2
State restrictions:
Patient can't order this test if they are located in Hawaii, Puerto Rico, New Jersey, New York, or Rhode Island
