HIV screening in pregnancy

> Transition from opt-in to opt-out HIV screening in pregnancy: A paradigm shift

The approach to HIV screening in pregnancy has undergone a significant transformation in recent years, shifting from an opt-in model to an opt-out model. Awanui laboratories will also be following this approach, in keeping with a recent publication from Auckland and feedback from local requestors.

An opt-in model was chosen when antenatal screening for HIV began in NZ where pregnant women are offered HIV testing but must explicitly consent to the test. This approach has several limitations:

  1. Low Uptake Rates: while a small minority of women decline, there are a significant number of requestor mistakes where HIV testing was intended, but the separate HIV box was not ticked. It was assumed in some cases that the HIV test is part of the normal first antenatal panel and so it was not noticed that an HIV test had not been performed.
  2. Missed Diagnoses: There has been at least one known missed diagnosis recently where it was assumed that the mother had been tested.
  3. Health Disparities: Some women may not fully understand opt-in testing, exacerbating existing health disparities.

The opt-out model integrates HIV testing into the standard battery of first antenatal tests where all pregnant women are informed that HIV testing will be conducted unless they decline. Also the reporting will change so that each test will appear separately as opposed to a panel which is the current situation.

A recent study from Auckland, published in the NZ Medical Journal (Feb 23, 2024) showed that testing rates increased from 86% to 98% after changing from opt-in to opt-out testing.

The shift from opt-in to opt-out HIV screening in pregnancy represents a major advance in public health strategy. By increasing the uptake of HIV testing, this approach ensures that more women receive the care they need, thereby reducing the rates of mother-to-child transmission of HIV and improving overall maternal and infant health outcomes. 

Clinical Microbiologists 
Awanui Labs