Laboratory-based syphilis lateral flow immunoassay testing for maternity care at Alice Springs Hospital: a pilot study

Abstract

Congenital syphilis is a preventable yet severe condition resulting from untreated maternal syphilis. Since 2016, Australia has recorded over 95 congenital syphilis cases, with 31/95 (33%) associated with perinatal death. Syphilis serology is complex and therefore performed in designated central laboratories. In the Northern Territory, specimen transport times associated with vast geographic distances lead to delayed results in remote regions. This study evaluates the introduction of the Abbott Determine™ Syphilis TP lateral flow immunoassay (LFI) at Alice Springs Hospital (ASH) to reduce turnaround times for maternal syphilis screening.

During the period 2 September – 1 December 2024, eighty-eight LFIs were performed on serum from 74 pregnant women at the ASH laboratory. LFI results were available within 24 hours for 99% of cases, with a median turnaround time of six hours compared to 61 hours for the screen done in Darwin (p < 0.001). No new syphilis cases were detected; all positive LFI results reflected past treated infections. LFI demonstrated 100% sensitivity and specificity compared to standard serology.

Although syphilis LFI cannot distinguish active from past infections, it significantly improves the timeliness of screening results, reducing risks of delayed treatment and of loss to follow-up. Implementing a syphilis LFI in remote laboratory settings offers a strategy to enhance syphilis diagnosis and prevention, with broader applicability in high-burden remote regions.