para>(From Morbidity & Mortality Weekly Report. June 21, 2013, 62:490 " “494.)View OriginalFigure 17 " “1HIV diagnostic testing algorithm.
(From Morbidity & Mortality Weekly Report. June 21, 2013, 62:490 " “494.)
View Original
Interpretation
- Positive in HIV infection; a positive screen test is considered "preliminary " ¯ and requires confirmation by definitive, specific testing, like HIV-1 RNA or Western blot assay. The patient with a positive test should be told of the result and advised on avoiding risk of transmitting HIV.
- A negative screen test is regarded as a true negative, and requires no confirmation; the patient may be informed that the test is negative.
Limitations
- Common causes of false-negative results can occur due to acute infection and failure to detect certain HIV subtypes.
- Rare causes of false-negative results include immune dysfunction due to defective humoral response or agammaglobulinemia, immunosuppression due to malignancy or medications, delay in seroconversion following early initiation of antiretroviral therapy, and fulminant HIV infection.
- False-positive test results for HIV infection have been documented after participation in an HIV vaccine trial.
- Indeterminate results may occur due to partial seroconversion during acute HIV infection, advanced HIV infection with decreased titers of p24 antibodies, or infection with HIV-2.
- Other causes for an indeterminate test result in persons who are not infected with HIV include
- Cross-reacting alloantibodies from pregnancy
- Autoantibodies (collagen " “vascular diseases, autoimmune diseases, and malignancy)
- Receipt of an experimental HIV-1 vaccine
- Influenza vaccination
Suggested Reading
1CLSI. Criteria for Laboratory Testing and Diagnosis of Human Immunodeficiency Virus Infection; Approved Guideline. CLSI document M53-A. Wayne, PA: Clinical and Laboratory Standards Institute; 2011.