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Human Immunodeficiency Virus HIV-1 antigen and HIV-1 & HIV-2 Antibodies



Other Names HIV Antigen and Antibody Combo Test
How to Order
Check the HIV box in the HIV section of the Virology/Immunology Test Request Form (form 42).
CTS submitters check the “Screen” box under the “Non-Rapid Tests Requested” heading on the CTS HIV Test Request yellow form 44.
Include time of specimen collection on the Test Request Form.
All clients
Enzyme Immunoassay
Daily on regular business days
Time to Reporting
1 to 3 working days after receipt of specimen
CPT Code

Specimen Collection Details

One 7 ml red top tube or serum separator tube (SST).
If SST tubes are used, follow instructions provided by the manufacturer.
Tubes with the additives: EDTA and sodium heparin are also acceptable. Please follow collection instructions to avoid improper dilution of samples when using tubes with additives.
Optimal Volume
Blood: 5-7 mL;
Serum 1-2 mL
Minimum Volume
Blood: 1-2 mL
Serum: 0.5 mL
Allow blood to clot, then keep specimen refrigerated until transport.
Specimens that will be tested within 3 days of collection can be stored on the clot. Do Not Freeze specimens stored on the clot.
All specimens must be tested within 7 days of collection. (See Comments)

If specimen will be tested 3-7 days after collection and you are able to, please remove the serum from the clot within 72 hours of specimen collection and submit serum only. (Note if this was completed within 72 hours on the Test Request Form.) The separated serum must be poured off into a sterile, leak proof, blood tube. A separated serum specimen may be frozen and remain frozen until receipt at the laboratory can be tested.
Transport specimen to maintain refrigerated temperatures until receipt at the OSPHL.
Blood specimens should be received by the OSPHL within 69 hours of specimen collection, but no later than 7 days after specimen collection. (See Comments)
If specimen is frozen, ship with dry ice to maintain frozen temperatures during transport.
Rejection Criteria
Serum specimens more than 7 days after specimen collection.
Specimens collected with additives other than those listed above.
Specimens contaminated with bacteria or particulate matter, hemolysis, gross lipemia, cadaver specimens, specimens collected using citrate anticoagulants, heat-inactivated specimens, specimens received at room temperature.
Specimens are subject to the requirements of the OSPHL Specimen Submission Policy and Criteria, available at
The test used will detect HIV-1 p24 antigen, HIV-1 & HIV-2 antibodies. Specimens reactive by Enzyme Immunoassay (EIA) will automatically be reflexed to an HIV differentiation test.

The HIV differentiation test requires serum to be removed from the clot within 72 hours of collection. Specimens received on the clot more than 69 hours (allowing 3 hours for OSPHL processing) after specimen collection will be tested by EIA only.
If the specimen is reactive on EIA, the laboratory result will show as preliminary positive with a request for a second specimen from the patient to complete the differentiation test. For the second specimen, serum must be removed from the clot within 72 hours of specimen collection by your clinic or by the OSPHL. Follow the Handling and Transport guidelines above.