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HIV-1/HIV-2 Diagnostic Testing

The Bloodborne Viruses Laboratory (BVL) provides a variety of referral testing services, including confirmation of reactive rapid tests, detection of suspected acute infections, and resolution of discrepant results.  Primary HIV screening is provided for a limited number of approved submitters.  Contact the laboratory for more information and to request approval to submit specimens. After receiving approval to submit specimens, follow the collection and shipping guidelines for the test requested, complete the DOH-49 test requisition form in full, and choose the appropriate test from the HIV testing menu:

  • Choose HIV diagnostic testing for primary HIV screening
     
  • Choose HIV diagnostic testing and HIV rapid test confirmation for confirming reactive HIV rapid tests
     
  • Choose HIV-1 qualitative RNA testing for specimens with a reactive HIV screening test and negative or indeterminate supplemental antibody test
     
  • Choose HIV-defendant testing for court-ordered defendant testing

For confirmation of reactive rapid tests and primary HIV screening, the BVL follows the Centers for Disease Control and Prevention (CDC) Updated Recommendations for Laboratory Testing for the Diagnosis of HIV Infection.  Whole blood, plasma and serum specimens submitted for HIV diagnostic testing are tested according to the BVL’s HIV Diagnostic Testing Algorithm beginning at Step 1.  Dried blood spots from rapid testing sites are tested using an alternative algorithm.

HIV Diagnostic Tests Available

Abbott Architect HIV Ag/Ab Combo assay (Abbott Laboratories): The ARCHITECT HIV Ag/Ab Combo assay is a chemiluminescent microparticle immunoassay (CMIA) that detects HIV-1 p24 antigen and IgM/IgG antibodies to HIV-1 (groups M and O) and HIV-2 in human serum and plasma.  A reactive result does not distinguish between the detection of HIV-1 p24 antigen, HIV-1 antibody, or HIV-2 antibody.  As with all immunoassays, there may be nonspecific reactions due to a variety of causes.  A repeatedly reactive result on the Abbott Architect HIV Ag/Ab Combo assay is considered preliminary and supplemental testing of the specimen is required to produce a final interpretation. 

Geenius HIV-1/2 Supplemental Assay (Bio-Rad Laboratories): The Geenius HIV-1/2 Supplemental Assay is a single-use, immunochromatographic assay for the confirmation and differentiation of individual antibodies to HIV-1 and HIV-2.  In the BVL’s HIV Diagnostic Testing Algorithm, the Geenius test is conducted on specimens that are repeatedly reactive on the HIV Ag/Ab Combo assay. The results of the Geenius test are read and interpreted by the Geenius Reader using FDA-approved software.

APTIMA HIV-1 RNA qualitative assay (Hologic): The APTIMA HIV-1 RNA Qualitative Assay is an in vitro nucleic acid test (NAT) for the detection of HIV-1 in human plasma and serum. It is intended for use as an aid in the diagnosis of HIV-1 infection, including acute or primary infection.  During the APTIMA assay, viral RNA is released and captured by HIV-1 specific oligonucleotides. The HIV-1 RNA is amplified by transcription-mediated amplification and detected by complementary chemiluminescent nucleic acid probes.  The APTIMA assay produces a qualitative result and is reported as detected or not detected. 

GS HIV-1 Western blot (Bio-Rad): The GS HIV-1 Western blot is a qualitative assay for the detection of HIV-1 antibodies in human serum, plasma and dried blood spots.  The Western blot detects IgG antibodies produced against specific HIV-1 proteins.  The Western blot is no longer recommended for HIV confirmation because it can produce false negative or indeterminate results on specimens that are reactive by the currently recommended screening tests and it misclassifies most HIV-2 infections. However the Western blot continues to be useful in certain circumstances.  In the BVL, HIV-1 Western blot is performed in the following situations:

  • Dried blood spot testing
  • Resolution of discrepant or inconclusive HIV test results.  Providers should contact the BVL for assistance.

HIV-2 Nucleic Acid Testing: The BVL uses a lab-developed, real-time PCR assay to detect and quantify HIV-2 RNA.