Disparities in testing and in test positivity for sexually transmitted infections (STIs) suggest missed opportunities for screening, and the need for more targeted strategies to improve prevention of STIs, according to research presented at the Infectious Disease Week (IDWeek) 2025 Annual Meeting in Atlanta.

One study found less than a third of patients received packaged testing for gonorrhea, chlamydia, HIV, and syphilis, despite recommendations for that practice, and substantial disparities in who gets packaged testing.

“Packaged testing remains grossly underutilized, and the rates of testing are low in our hospital system,” Tri Pham, MD, MPH, resident at the Washington University School of Medicine in St. Louis, told attendees. “Universally, women and young patients had the lowest odds of testing, but they have the highest burden of disease in general,” he said. “This study is an initial first step to informing the gaps in our care, and how to inform and shape interventions down the line.”

The other study found significantly higher test positivity rates for gonorrhea and chlamydia among adolescents, Black and Hispanic patients, and those with public insurance or no insurance — particularly among those tested in the emergency department (ED).

“It is really just important to know that the ED serves as an important point of access to many women, including those populations that have the highest positivity,” Sarah Naz-McLean, MSc, PhD candidate in epidemiology at the University of Toronto, Toronto Ontario, Canada, and senior project manager in the Division of Infectious Disease, Brigham and Women’s Hospital, Boston, told attendees. “What we really need is to continue focusing on equity- and justice-driven strategies to improve access to screening across all settings, both primary care and ob/gyn, as well as urgent care setting.”

Meena Ramchandani, MD, MPH, associate professor of infectious diseases at the University of Washington School of Medicine, Seattle, who was not involved in either study, found both presentations helpful in identifying areas to target for interventions to reduce disparities.

“Chlamydia and gonorrhea can be asymptomatic in women and if left untreated can lead to significant morbidity, including pelvic inflammatory disease and infertility. Screening for these infections is important but underutilized,” Ramchandani told Medscape Medical News. “Increased awareness of STIs, education of healthcare providers, increased access to testing and treatment, and supporting and strengthening public health efforts will help to improve STI control.”

The US has been experiencing rise in STIs over the past decade, and significant disparities persist within this increase, Pham said. Nearly half (48%) of all reported STIs occurred in people aged 15-24 years in 2024, for example, and although Black individuals account for just 13% of the US population, they account for nearly a third (32%) of all reported STI cases.

Meanwhile, coinfections of STIs are common. For instance, more than a third (37%) of men who have sex with men who were diagnosed with syphilis in 2024 were men who already had HIV. Hence, packaged testing for HIV and syphilis is recommended for patients who undergo screening for gonorrhea and chlamydia, Pham said.

To understand how often this practice actually occurs, however, researchers analyzed patient data for approximately 170,000 adults undergoing concurrent gonorrhea and chlamydia testing at 318,917 patient encounters between January 2019 and December 2024 at a large Midwestern academic hospital system, which includes 14 hospitals and more than 230 practice locations across Missouri, southwestern Illinois, northern Arkansas, and small parts of eastern Kentucky and eastern Tennessee.

They examined data on age, sex, race, ethnicity, insurance type, zip code, and testing location (inpatient, outpatient, or ED) for those who did and did not receive packaged testing — testing for gonorrhea, chlamydia, HIV, and syphilis at a single encounter.

The population was a median 29 years old and predominantly female. Nearly half were Black patients (48%), 44% were White, 2% were Asian, and 2% were Hispanic. A third (34%) had private insurance and 21% had Medicaid, whereas 39% paid out of pocket. The largest income group (42%) were those earning a median $50,000-74,000 based on zip code, with a quarter earning less than that, 20% earning $75,000-99,000, and 13% earning more than $100,000 annually.

Just 31.8% of encounters involved packaged testing, though rates of packaged testing did increase each year. Far more packaged testing occurred in outpatient infectious disease visits (79%) than in primary care visits (47%), outpatient ob/gyn (37%), and ED (10%) visits. In fact, patients had over triple the odds of packaged testing with outpatient infectious disease visits (adjusted odds ratio [aOR], 3.34) than with primary care visits, while they were least likely to undergo it in the ED (aOR, 0.11).

Despite adolescents and young adults being at highest risk for STIs, older patients were more likely to receive packaged testing, especially ages 25-34 (aOR, 1.79) and ages 35-44 (aOR, 1.82, both significant). Women were almost half as likely as men to undergo packaged testing (aOR, 0.53), and Black (aOR, 1.21) and Hispanic (aOR, 1.28) people were more likely to receive packaged testing.

No significant differences in packaged testing rates emerged based on income levels, but those on Medicaid were modestly, significantly more likely to get packaged testing (aOR, 1.16).

“There are several possible explanations [for that], but a potential one is that missed quality metrics may affect reimbursements in Medicaid,” Pham said. “Thus, perhaps there is higher screening awareness among providers to conduct these screening practices.”

He suggested that the low rates of packaged testing in the ED may reflect the fact that gonorrhea and chlamydia testing is usually urine-based, whereas HIV and syphilis testing is usually serum-based and require follow-up, “both of which may limit uptake of screening access within the ED.”

“There are such unique infrastructural challenges and systems issues between these locations and systems in our healthcare and so we have to be thoughtful, and we want to be specific in how we want to address interventions and policies to help expand testing practices within our hospitals,” Pham said.

Ramchandani told Medscape Medical News that this study “was helpful for them to study the gaps in care and how to inform and shape interventions in the future to expand testing practices within the hospital system.”

In introducing her study, Naz-McLean also noted the disproportionately higher burden of chlamydia and gonorrhea among adolescent and young adult women, yet only about half of eligible women are screened, she said.

Her study assessed the demographic patterns of those tested for these STIs in a large Massachusetts integrated healthcare system, Mass General Brigham, which includes 12 hospitals, 10 EDs, 5 community health centers, and 1300 primary care providers. They analyzed retrospective data from the healthcare system’s Research Patient Data Registry of female patients, aged 15-29 years, with at least one lab test for gonorrhea and chlamydia between January 2016 and January 2024.

Across 134,607 clinical encounters with adequate data, the chlamydia positivity rate was 3% and the gonorrhea positivity rate was 0.3%. Most of the testing occurred in primary care (46.2%) or ob/gyn care (33.8%). While only 5% of testing occurred in the ED, it was more common among public insurance (14.2%), uninsured (9.9%), Black (8.7%), Hispanic (7.8%), and adolescent (7.3%) patients.

It was also where the highest test positivity rate occurred for chlamydia in those aged 15-19 years (test positivity, 9.8%); in Black (7.1%), Hispanic (7.1%), and Asian (8%) patients; and in those with public insurance (7.7%) or no insurance (8.1%). Overall, as well, those with the highest test positivity rates were adolescents (5.2%), Black (4.3%) and Hispanic (4.6%) patients, and those with public (4.6%) or no (4.9%) insurance.

About a quarter of all testing (23.5%) occurred in patients presenting with symptoms, which was particularly true for Black (29.3%; adjusted risk ratio [aRR], 1.36) and Hispanic (29.3%; aRR, 1.37) women.

Among the disparities identified in the study were that Black and Hispanic patients had higher positivity rates, more frequent symptomatic presentation, and greater acute care use, Naz-McLean said.

“There was also higher positivity and higher acute care use among adolescents and women with public insurance or no insurance,” she said. “They were approximately equal or less likely to present with symptoms, and jointly, these could potentially be indicators that signal reduced access to routine asymptomatic screening.”

Ramchandani found this research helpful in understanding “more about disparities in STI care and the need for more resources and support for patients from underserved populations,” she told Medscape Medical News. “It also speaks to the need to strategize to expand access to timely STI screening in all settings and support more testing in primary, public health, and outpatient care.”

Pham reported having no disclosures; his study was funded by the CDC, the Foundation for Barnes-Jewish Hospital, the Washington University Institute for Public Health, the Washington University Institute of Clinical and Translational Sciences, and the National Institutes of Health. Naz-McLean had no disclosures; her study was funded by the University of Toronto. Ramchandani had no disclosures.

Tara Haelle is a science/health journalist based in Dallas.