Human immunodeficiency virus (HIV) (newly acquired) case definition

This document contains the case definitions for human immunodeficiency virus - newly acquired which is nationally notifiable within Australia. This definition should be used to determine whether a case should be notified.

Page last updated: 12 March 2004

Australian national notifiable diseases case definitions - Human immunodeficiency virus (HIV) - newly acquired

Newly acquired HIV infection may be diagnosed in individuals aged 18 months or older at the time of blood sample collection. A diagnosis of newly acquired HIV infection excludes a diagnosis of HIV infection (unspecified).

Reporting

Both confirmed cases and probable cases should be notified.

Confirmed case

A confirmed case requires laboratory definitive evidence only.

Laboratory definitive evidence

1. Repeatedly reactive result on a screening test for HIV antibody followed by a positive result on a western blot AND laboratory evidence of a negative or indeterminate HIV antibody result in the 12 months prior to blood sample collection

OR

2. A group IV indeterminate western blot AND detection of HIV by at least one of the following virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation). A group IV indeterminate western blot is defined by the presence of a glycoprotein band (gp41, gp120 or gp160) and one or two other HIV specific bands.

Probable case

A probable case requires Laboratory suggestive evidence and clinical evidence.

Laboratory suggestive evidence

1. Detection of HIV by at least one of the following virologic assays (nucleic acid testing for proviral DNA; HIV p24 antigen, with neutralisation; virus isolation)

OR

2. Repeatedly reactive result on a screening test for HIV antibody followed by a positive result on a western blot.

Clinical evidence

HIV seroconversion illness within the 12 months prior to blood sample collection.

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