Biomarker identifies early sepsis in children, pregnant women

Key takeaways:

• IL-6 levels peak 6 hours after infection, compared with 24 hours for traditional biomarkers.
• The biomarker was an effective early indicator of sepsis in children and pregnant women.

VIENNA — Interleukin-6 could help physicians diagnose sepsis early in children and pregnant women, according to a real-world study presented at the ESCMID Global meeting 2025.

“Traditional biomarkers have a lag time between the infection onset and the time the marker begins to rise again before it reaches its peak concentration,” Seán O. Whelan, MB, BAO, BCh, MRCPI, a clinical microbiology trainee at Children’s Health Ireland at Temple Street in Dublin, told Healio.

C-reactive protein and procalcitonin begin to rise 6 hours after infection and peak at 24 hours, Whelan explained, whereas IL-6 begins to rise almost immediately and peaks at 6 hours. It is especially difficult to detect sepsis in pregnant women because the changes seen in sepsis also appear during labor, hemorrhage and eclampsia, Whelan said.

Early detection and intervention are critical for preventing poor outcomes, so Whelan and colleagues decided to evaluate how IL-6 performed for detecting and ruling out sepsis.

The researchers conducted a retrospective cohort study of 69 babies aged older than 1 year, 111 children and 72 pregnant women with suspected sepsis. Providers measured IL-6 levels in all 252 patients upon intake and again 1 day later.

The biomarker performed well for identifying and ruling out bacterial infections in children and pregnant women, but it was not as accurate in infants, the researchers reported.

In children and pregnant women, IL-6 detected and ruled out bacterial infections in more than 80% of patients. In infants, the biomarker was highly accurate at ruling out bacterial infections (97.1% specificity). However, it had a sensitivity of only 67.6%.

The researchers calculated area under the receiver operating characteristic curve (AUROC) scores of 0.91 for children, 0.94 for pregnant women and 0.86 for babies, according to a related press release.

Whelan said that 91% of patients had lower IL-6 levels at their second measurement compared with their first. In contrast, only 25% and 17% had lower levels of C-reactive protein and procalcitonin at the second time point.

These findings show that IL-6 could be a good early indicator of sepsis in children and pregnant women, Whelan said, which would ensure that patients get treated as soon as possible.

“This is especially important for patient populations such as children and pregnant women where frequently care may be delivered in a setting where there is not on-site critical care support,” Whelan said. “A very elevated IL-6, accompanied by clinical concern, can act as an additional red flag that this patient is at risk of deterioration and may need transfer of care to a higher acuity setting.”

For more information:

Seán O. Whelan can be reached on X at @seanolannwhelan and Bluesky at @swhelan.bsky.social.

References:

• Whelan SO, et al. Abstract 04331. Presented at: ESCMID Global; April 11-15, 2025; Vienna.
• Breakthrough study identifies promising biomarker for early sepsis detection in neonates, children, and pregnant women. https://www.eurekalert.org/news-releases/1079319. Published April 11, 2025.