The Impact of Age, Comorbidity, and Current Medication Use on Plasma p-tau217 in Adolescents: A Pilot Study

Adolescence is a critical period of neurodevelopment with the emergence of chronic medical conditions and increasing exposure to long-term medications. Phosphorylated tau at threonine 217 (p-tau217) is a sensitive blood-based biomarker of neuropathology in older adults, yet its developmental behavior and susceptibility to common clinical factors in youth are unclear. Here we tested whether p-tau217 varies with age, comorbidity, or medication use during adolescence and whether collection method (venous vs Tasso+ capillary) yields comparable concentrations.

In an adolescent cohort, plasma p-tau217 was measured by Simoa HD-X. Paired venous and Tasso+ capillary samples were also analyzed from adult volunteers for methodological comparison.

In adolescents (n = 41; mean age 16 ± 2.6 years), p-tau217 did not correlate with age or body mass index z score and did not differ by psychiatric, cardiometabolic, or gastrointestinal comorbidity nor by corresponding medication use. In contrast, p-tau217 concentrations were >10-fold higher in Tasso+ capillary plasma than venous plasma, a discordance replicated in paired adult samples.

There was no clear evidence of associations between plasma p-tau217 and common clinical variables in adolescence, yet plasma p-tau217 is highly sensitive to biospecimen collection method. Venous and Tasso+ capillary plasma should not be directly compared or pooled until methodological differences are resolved. These data provide the first look at the relationship between p-tau217 and clinical factors during adolescence and provide a critical methodological caution for pediatric neuroscience and decentralized biomarker studies.