HIV Ag/Ab Combo
CPT Code(s):
86703
Turnaround Time:
24 - 48 hours
Specimen Requirements
Preferred Specimen:
Serum and Plasma
Minimum Volume:
1.0 mL
Transport Container:
Serum Separator Tube (SST) and Lavender Top Tube (EDTA) or Red Top Tube
Transport Temperature:
Room Temperature
Collection Instructions:
Allow blood to clot completely prior to centrifugation. Separate serum from cells within 45 minutes of collection. EDTA must be frozen within 24 hours of collection.
Rejection Criteria:
Sodium Citrate plasma; gross hemolysis; lipemia; improper labeling
Stability Criteria
Room Temperature:
24 hours
Refrigerated:
14 days
Frozen:
30 days
Clinical Significance
The HIV Ag, Ab Combo holds specific clinical significance and diagnostic use in the detection of both HIV antigens and antibodies in a patient's blood. It is a fourth-generation HIV screening that offers improved sensitivity and specificity compared to earlier HIV tests.
The specific clinical significance and diagnostic use of the HIV Ag, Ab Combo include:
1. Early HIV Infection Detection: The test is highly effective in detecting early HIV infection during the acute phase when the viral load is high and antibodies are still developing. It can detect both HIV antigens (p24 antigen) and antibodies to HIV, allowing for earlier diagnosis and timely initiation of treatment.
2. Screening for HIV Infection: The HIV Ag, Ab Combo is widely used as a first-line screening test for HIV infection. It provides a comprehensive assessment by detecting both viral antigens and antibodies, improving the likelihood of detecting HIV infection, including recent or acute cases.
3. Differentiating HIV-1 and HIV-2: The test can differentiate between HIV-1 and HIV-2 infections. HIV-1 is the most common type worldwide, while HIV-2 is primarily found in West Africa. Differentiating between the two is crucial for appropriate management and selection of antiretroviral therapy.
4. Window Period Reduction: The HIV Ag, Ab Combo has a shorter "window period" compared to previous-generation tests. The window period is the time between HIV infection and the appearance of detectable antibodies. By detecting both antigens and antibodies, the test helps reduce the window period, enabling earlier detection of HIV infection.
5. Prevention of HIV Transmission: Timely diagnosis using the HIV Ag, Ab Combo allows for early initiation of antiretroviral therapy, which can significantly reduce the viral load in the blood. This not only improves the patient's health but also helps prevent HIV transmission to sexual partners or from mother to child during childbirth.
6. Confirmation and Follow-Up Testing: A reactive result from the HIV Ag, Ab Combo is followed by additional confirmatory tests, such as Western blot or HIV RNA tests, to confirm the HIV infection. Serial testing over time helps monitor disease progression, evaluate treatment response, and assess the effectiveness of prevention strategies.
It is important to note that a reactive result from the HIV Ag, Ab Combo does not confirm the presence of HIV infection. Additional confirmatory testing is necessary to establish the diagnosis.
In summary, the HIV Ag, Ab Combo is specifically used for early detection and screening of HIV infection. It detects both viral antigens and antibodies, reducing the window period and enabling earlier diagnosis. The test plays a crucial role in preventing HIV transmission, differentiating HIV types, and guiding treatment decisions. Timely diagnosis and appropriate management are vital in improving patient outcomes and reducing the spread of HIV.