HIV 1/2 Antibody and Antigen, Screening

HTLV-III Antibodies, HIV Antibodies, HIV Ag/Ab Test, HIV Combo, HIV 1/2 Screen, HIV Screen, HIV 1/2 Testing Algorithm

Test Codes

EPIC: LAB1231685, Beaker: HIV4G

Department

Chemistry

Specimen Collection Criteria

Collection Requirements: 

• One dedicated Lavender EDTA tube. This tube cannot be shared with any other test. 
• The lavender EDTA tube should be filled appropriately (3.0 mL); partially filled tubes may result in testing delays and possible requests for patient redraw.
• No other test can be added on to this dedicated tube.

If you have any questions, please contact Client Services (1-800-551-0488, option 5) 

Physician Office/Draw Specimen Preparation

Maintain whole blood refrigerated (2–8°C or 36–46°F), or at room temperature (20–26°C or 68–78.8°F) prior to transport. For delays in transport greater than 24 hours, centrifuge the specimen, transfer plasma to a plastic transport tube, and freeze (-20°C/-4°F or below). (Minimum: 1.0 mL plasma)

Preparation for Courier Transport

Transport: Whole blood refrigerated (2–8°C or 36–46°F), or plasma, frozen (-20°C/-4°F or below). (Minimum: 3.0 mL whole blood or 1.0 mL plasma)

Rejection Criteria

• Heat inactivated serum.
• Severely lipemic or hemolyzed specimens.
• Specimens that have obvious bacterial contamination.

In-Lab Processing

Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

EDTA Plasma aliquots
Room Temperature (20-25°C or 68-77°F): 4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): For longer storage.

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day.
Negative results available within 24 hours.
Positive results for HIV-1 Antibodies available within 24 hours.
If send out testing for HIV-1 RNA is necessary, results may take an additional week. See links to the Centers for Disease Control and Prevention's (CDC) updated guidelines/-algorithm below.

Reference Range

Negative.

Test Methodology

Chemiluminescence Immunoassay.

Interpretation

• A negative test result does not rule out the possibility of exposure to, or infection with, HIV.
• An initial positive screen will be followed by confirmatory testing based on the CDC’s updated algorithm:
  HIV Testing Algorithm for Serum or Plasma Specimens (4)
• Interpretation Guidelines:
  HIV Diagnostic Testing Algorithm for Serum and Plasma Specimens (5)

Clinical Utility

The initial screen is a 4^th generation assay that detects both HIV-1 p24 antigen and antibodies to HIV-1 (groups M and O) and HIV-2. This screen will detect acute HIV infection, on average 7 to 10 days earlier than the previously used antibody-only screen.

HIV-1 IgG is first detectable 3-12 weeks after infection in nearly all cases except neonates. Once established, HIV antibody levels usually persist throughout the lifetime of the patient. The presence of antibody does not imply immunity to the virus but rather, that the patient is assumed to be infected, and infectious. (3) Little is known about the antibody response to HIV-2 infection. The response is presumed to be similar to HIV-1. (3)

Positive screens are followed by confirmatory testing per CDC’s HIV testing algorithm: 
HIV Testing Algorithm for Serum or Plasma Specimens (4)

Clinical Disease

Primary HIV infections are symptomatic in 50-70% of patients. These patients present with a variety of symptoms including Influenza-like or mononucleosis-like illness to more severe neurological symptoms. These symptoms may persist for a few days or up to two months. Rapid progression to AIDS is seen in patients that experience a longer acute illness. Most patients however, remain asymptomatic for 1 to greater than 10 years before the clinical symptoms of AIDS present. (2)

Disease Reporting

This is a reportable infection and positive results will be reported to the Oakland County Health Department. In Michigan, both physicians and laboratories are responsible for reporting AIDS/HIV respectively. For more information on reportable diseases, contact the Epidemiology Department at (248) 551-4040.

Epidemiology

HIV-1 caused a worldwide pandemic of acquired immunodeficiency syndrome and AIDS-related complex. (1) In 1995, the World Health Organization estimated that 18 million adults and 1.5 million children are infected with HIV resulting in 4.5 million AIDS cases worldwide. (1)

Incubation Period

The median time from HIV infection to AIDS is 8-10 years. Homosexual men and some neonates may progress to AIDS more rapidly than other groups. (1)

Transmission

HIV-1 is transmitted by blood, blood products, and body fluids. Major modes of HIV-1 transmission include sexual intercourse, parenteral transmission through shared or inadequately sterilized needles, transfusion of HIV-1 infected blood and blood factor concentrates, and mother-to-child transmission either in utero, at birth, or through breast feeding. (1)

Reference

1. CDC. 2006. The global HIV/AIDS pandemic, 2006. MMWR. 55: 841-844.
2. CDC. 2006. Epidemiology of HIV/AIDS---United States. 1981-2005. MMWR. 55: 589-592.
3. Schusbach, J. 2003. Human Immunodeficiency viruses. Manual of Clinical Microbiology, 8^th edition. P.R. Murray et al. (eds). ASM Press. Washington, D.C., pp. 1253-1281.
4. National Center for HIV/AIDS, Viral Hepatitis, and TB Prevention (U.S.). Division of HIV/AIDS Prevention, Association of Public Health Laboratories. 2018 Quick Reference Guide: Recommended Laboratory HIV Testing Algorithm for Serum or Plasma Specimens. CDC Stacks. Published January 2018. https://stacks.cdc.gov/view/cdc/50872.

CPT Codes

Initial Screen: 87389.
If screen is positive: 86701, 86702.
Further confirmation testing (if necessary): 87535, 87538.

Contacts

Last Updated

11/6/2026