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HIV Antibody and Antigen Combination Test

Item Value
Approval req'd? No
Available Stat? No
Test code HIVAA
Test group HIV
Performed by Immunology
In House Availability Monday - Friday (day shift only)
Method Chemiluminescent Immunoassay
Collection Instructions For tests not ordered directly via APEX, the ordering provider should document patient consent in the medical record
Container type Red top
Amount to Collect 1 mL blood
Sample type Serum
Preferred volume 0.5 mL serum
UCSF Rejection Criteria Grossly hemolyzed samples
Processing notes Refrigerate samples.
Normal range Negative
Synonyms Human Immunodeficiency virus: HIV-1, HIV-2 Antibody & HIV-1 p24 Antigen
Stability Room temperature 3 days
Turn around times 3-5 days (3-5 additional days for confirmation of positives)
Reflex? HIV-1/2 Antibody Differentiation will automatically be performed on all positive samples at an additional charge. Indeterminate or negative results on the secondary assay will be reflex to HIV-1 NAT testing (send out test).
Additional information This test detects antibodies to HIV-1 and HIV-2 along with the p24 antigen. Reactive results will be tested secondarily with an immunoassay to differentiate HIV-1 antibodies from HIV-2 antibodies. Indeterminate or negative results on the secondary assay will be reflex tested for HIV nucleic acid (HIV-1 NAT, sendout test). Positive screening with negative or equivocal secondary testing could indicate acute HIV infection or a false positive result. This testing methodology follows the CDC recommendations published in June 2014 (for further information, see http://www.cdc.gov/hiv/guidelines/testing.html).

Note: Per the CDC recommendations, HIV-1 Western blot testing is generally not indicated with the availability of the HIV-1 NAT test. HIV-1 NAT can be ordered separately in cases where a false positive screening result is suspected.

Assay interpretation for secondary testing:

HIV-1 Result HIV-2 Result Assay Interpretation
Nonreactive Nonreactive HIV NEGATIVE
Indeterminate Nonreactive HIV-1 INDETERMINATE a
Nonreactive Indeterminate HIV-2 INDETERMINATE b
Indeterminate Indeterminate HIV INDETERMINATE c
Reactive Nonreactive HIV-1 POSITIVE
Reactive Indeterminate HIV-1 POSITIVE
Nonreactive Reactive HIV-2 POSITIVE
Indeterminate Reactive HIV-2 POSITIVE
Reactive Reactive HIV POSITIVE Untypable (undifferentiated): Antibodies to HIV-1 and HIV-2 confirmed in the sample. This may occur in an HIV-2 positive sample with significant cross-reactivity to HIV-1, or may be due to co-infection with both HIV-1 and HIV-2 (rare).*

*Note: Differentiation features managed by proprietary algorithm.

a HIV-1 band(s) detected but did not meet the criteria for HIV-1 Positive
b HIV-2 band(s) detected but did not meet the criteria for HIV-2 Positive
c HIV band(s) detected but did not meet the criteria for HIV-1 Positive or HIV-2 Positive

CPT coding 87389
LOINC code 56888-1
Last Updated 4/14/2017 12:23:22 PM
Entry Number 1554
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