HIV ANTIBODIES

---

Specimen: 10 mL blood in plain tube. Informed consent must be obtained from the patient, prior to collection.

Method: Immunoassay for detection of both HIV-1 and HIV-2 antibodies. Specialised laboratories confirm positive immunoassay results by immunoblot methods.

Reference Interval: Positive is significant, if confirmed by second assay system.

Application: Diagnosis of HIV infection. Screening of blood, tissue or organ donors. Following exposure, the seronegative “window” period may be from 3 weeks to several months. Occasional subtypes of HIV may be undetectable by some EIA methods.

Interpretation: Positive indicates HIV infection and must be confirmed by immunoblot and by testing on a separate sample. False positives are rare, and can be further assessed by immunoblot, tests for HIV antigen or, preferably, HIV-1 RNA and repeat HIV antibody testing; see HIV-1 ANTIGEN , HIV-1 RNA . In terminal disease, HIV antibodies may be negative. HIV-1 is common worldwide; HIV-2 is less common and is largely confined to Africa.

Reference: Schleupner CJ. In: Mandell GL et al eds. Principles and Practice of Infectious Diseases. 4th ed. Churchill Livingstone 1995. Gaines H et al. Lancet 1987; I: 1249-1253.

---