Lab Matters Spring 2022 | Page 16


Old Pathogens Meet New Testing Practices : Updates to STI and HIV Testing Routines

By Ashley Nenninger , PhD , Scientific Affairs , Hologic and Karen Harrington , PhD , Scientific Affairs , Hologic
While the pandemic has necessitated significant focus on laboratory testing of a single pathogen , the last two years have also brought critical changes to testing for other important pathogens such as those associated with sexually transmitted infections ( STIs ). In March 2020 , many clinical and community-based services shut down or moved to virtual platforms . There were dramatic declines ( 50-60 %) in HIV and STI testing , and many areas are still observing lower testing numbers relative to pre-pandemic levels . 1
Despite significant impacts to testing , important recent updates to recommended STI laboratory testing have been issued in the 2021 US Centers for Disease Control and Prevention ( CDC ) STI Guidelines . With this new guidance , there is an opportunity to implement testing updates as laboratories seek to return to routine practices , and help bring STI testing rates back . New considerations for chlamydia and gonorrhea testing , such as implementing opt-out screening of young women (< 25 years ) and including extragenital testing using tests cleared by the US Food and Drug Administration ( FDA ) for these sample types , were introduced in 2021 . The guidelines include other newly FDA-cleared testing options so laboratories can consider bringing on new tests for emerging pathogens like Mycoplasma genitalium or tests that detect bacterial vaginosis via molecular methods . Additionally , universal oncein-a-lifetime hepatitis C virus ( HCV ) screening is now recommended for all adults ( ≥18 years ) and all women during each pregnancy , except where prevalence is < 0.1 %.
Along with STI guideline updates , updates to HIV testing are actively being considered . The current CDC three-step HIV testing algorithm has been in place since 2014 . An alternative algorithm in which a quantitative nucleic acid test ( NAT ) with a diagnostic indication as the second step in the algorithm has been suggested , 2 but until a year ago such a
A laboratory technician prepares to load Aptima assay reagents onto the Panther system . Photo : Hologic
NAT did not exist . FDA approval for a diagnostic claim for the Aptima ® HIV-1 Quant Dx assay was granted in late 2020 . It is the first and only HIV-1 NAT that can be used as an aid in diagnosis and for viral load monitoring .
Providing diagnosis confirmation and viral load directly following Ag / Ab HIV screening is advantageous by decreasing result turnaround time , leading to faster linkage to care , initiation of antiretroviral therapy ( ART ), reduced transmission and better patient outcomes . Furthermore , HIV-1 NAT as a second step would reduce the number of ambiguous Ab differentiation results , lowering testing costs . CDC HIV laboratory surveillance has conclusively demonstrated that prevalence of HIV-2 continues to be low in the US and HIV-1 / 2 differentiation can be done as the third step if necessary . The ability to meet the Ending the HIV Epidemic : A Plan for America goal of reducing HIV diagnoses by 90 % by 2030 will require a renewed commitment to improving HIV testing that includes consideration of new testing algorithms to streamline diagnosis and reduce transmission .
During the COVID-19 pandemic , continued public health messaging , interventions and outreach programs to restore STI and HIV testing and treatment to pre-pandemic levels remains important . Diagnostic platforms that can do much of this testing on a single instrument , like the Panther system , offer efficiencies in consolidation of testing on a single device . As laboratories return to routine testing , using broad menu , high-throughput platforms with tests that have comprehensive indications is more important than ever . •
1 . Menza TW . Dramatic decline in public sector HIV / STI testing during SARS-CoV-2 pandemic , Oregon . Oral Abstract presentation CROI 2021 .
2 . Mascoitra S , et al . Could HIV-1 RNA Testing be an Option as the Second Step in the HIV Diagnostic Algorithm ? Sex Trans Dis . 2020 ; 47 : S26-S31 .
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14 LAB MATTERS Spring 2022
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