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HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes : 91431
Test CodeHIVAAX or 91431
Alias/See Also
Fourth Generation HIV,4th Generation HIV
CPT Codes
87389; if 1st reflex add 86701 and 86702; if 2nd reflex add 87535
Includes
If HIV Antigen and Antibody, 4th Generation Screen is Repeatedly Reactive, then HIV-1/2 Antibody Differentiation will be performed at an additional charge (non-orderable Test code HIVSCR; interface code %37907, CPT codes: 86701, 86702).
If HIV-1/2 Antibody Differentiation is Indeterminate or Negative, then HIV-1 RNA, Qualitative Real-Time PCR (non-orderable Test code HIVQRQ; interface code %16185) will be performed at an additional charge CPT code: 87535.
If HIV-1/2 Antibody Differentiation is Indeterminate or Negative, then HIV-1 RNA, Qualitative Real-Time PCR (non-orderable Test code HIVQRQ; interface code %16185) will be performed at an additional charge CPT code: 87535.
Transport Container
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.
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 Temperature
Room temperature.
Specimen Stability
Room temperature: 72 hours; Refrigerated: 5 days; Frozen: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis; Frozen serum separator tube
Methodology
Immunoassay
Setup Schedule
Sunday - Saturday
Report Available
1 day
Reference Range
Non-Reactive
Clinical Significance
HIV-1/2 Antigen and Antibodies, Fourth Generation, with Reflexes - 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].
References
1. Moyer V, USPTF. Ann Intern Med. 2013;159:51-60.
2. CDC. New CDC recommendations for HIV testing in laboratories. https://www.cdc.gov/nchhstp/newsroom/docs/2014/hiv-testing-labs-flowchart.pdf. Published June 2014. Accessed May 20, 2019.
3. CDC. PrEP. https://www.cdc.gov/hiv/basics/prep.html. Published February 2019. Accessed May 20, 2019.
4. Livant E, et al. J Clin Virol. 2017;94:15-21.
5. CDC. HIV testing. https://www.cdc.gov/hiv/testing/index.html. Published March 2019. Accessed May 20, 2019.
6. Nasrullah M, et al. AIDS. 2013;27:731-737.
7. Chavez P, et al. J Clin Virol. 2011;52(Suppl 1):S51-S55.
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].
References
1. Moyer V, USPTF. Ann Intern Med. 2013;159:51-60.
2. CDC. New CDC recommendations for HIV testing in laboratories. https://www.cdc.gov/nchhstp/newsroom/docs/2014/hiv-testing-labs-flowchart.pdf. Published June 2014. Accessed May 20, 2019.
3. CDC. PrEP. https://www.cdc.gov/hiv/basics/prep.html. Published February 2019. Accessed May 20, 2019.
4. Livant E, et al. J Clin Virol. 2017;94:15-21.
5. CDC. HIV testing. https://www.cdc.gov/hiv/testing/index.html. Published March 2019. Accessed May 20, 2019.
6. Nasrullah M, et al. AIDS. 2013;27:731-737.
7. Chavez P, et al. J Clin Virol. 2011;52(Suppl 1):S51-S55.
Performing Laboratory
med fusion
