Children’s Heart Tests Rely on Adult Data, Global Survey Finds

When a patient arrives at an emergency department with chest pain, one of the first blood tests a physician orders measures cardiac troponin, a protein released into the bloodstream when heart muscle cells are damaged. In adult medicine, this test has transformed the diagnosis of heart attacks, allowing clinicians to confirm or rule out injury within hours and to stratify patients for urgent intervention. Decades of research have produced well-validated reference intervals, the numerical ranges that separate a normal result from an abnormal one, and international guidelines specify exactly which troponin thresholds should trigger which clinical decisions. For children, that foundation is largely missing, and a new global survey suggests the consequences are more widespread than many clinicians realize.

The survey, conducted by the International Federation of Clinical Chemistry and Laboratory Medicine’s Committee on Emerging Technologies in Pediatric Laboratory Medicine, set out to map how pediatric cardiac troponin testing is actually practiced around the world. The results, published in the journal Clinical Chemistry and Laboratory Medicine under the title Mapping pediatric cardiac troponin testing worldwide: results from the IFCC survey on emerging applications, standardization needs and access, reveal a field running on borrowed data. Among eligible respondents, 58.5 percent reported offering cardiac troponin testing in-house, yet 65.5 percent of those laboratories lacked child-specific reference intervals. In practice, most laboratories testing children rely on reference intervals designed for adults, often those supplied by assay manufacturers, even though the biology of a child’s heart and the conditions that damage it differ profoundly from those of an adult.

Reference intervals are the quiet workhorses of laboratory medicine. When a troponin result comes back, the number on the report means little on its own; it is the comparison against a validated normal range that tells the clinician whether heart muscle injury has occurred. If that range is wrong, two kinds of error follow. A threshold set too high, calibrated to adult populations with different baseline physiology, may miss genuine cardiac injury in a child, delaying diagnosis of myocarditis or another serious condition. A threshold set too low may flag healthy children as abnormal, triggering unnecessary echocardiograms, hospital admissions, and parental anxiety. Without pediatric-specific data, laboratories cannot know which kind of error they are making, or how often.

The survey found that a handful of clinics have attempted to establish child-specific troponin benchmarks, but the picture they paint is one of fragmentation rather than progress. Different clinics use different cutoffs, and there is no agreement on how the correct reference interval should be derived in the first place. Some may have used small local cohorts of healthy children, others may have adapted manufacturer data or published studies conducted on different analytical platforms. Because troponin assays themselves vary between manufacturers, with different antibodies and different detection limits, a cutoff validated on one platform cannot simply be transferred to another. The result is a patchwork in which the same child, with the same underlying condition, might receive a different interpretation depending on which hospital’s laboratory processed the sample.

Most clinicians and laboratory specialists who responded to the survey identified this absence of consistent, validated child-specific guidelines as a major obstacle to providing children with reliable heart care. The problem is not simply that the data are missing; it is that the clinical questions asked of troponin testing in children are fundamentally different from those asked in adults. Heart attacks are rare in childhood, so the adult paradigm of using troponin to confirm or exclude myocardial infarction rarely applies. Instead, pediatricians deploy troponin testing across a remarkably wide range of conditions that have little in common with adult coronary disease, including heart infections such as myocarditis, Kawasaki disease with its inflammatory damage to coronary arteries, and cardiac injury caused by cancer treatment, a growing concern as survival rates for childhood cancer continue to climb.

This diversity of clinical contexts changes what a reference interval would even mean. A single normal range borrowed from a population of healthy children assumes that one threshold can serve every purpose, but the survey’s authors argue that this assumption fails. A child undergoing chemotherapy may sustain low-level cardiac injury that matters enormously for long-term outcomes but produces troponin values far below the threshold relevant to acute myocarditis. Conversely, the inflammatory storm of Kawasaki disease may drive troponin concentrations to levels that would be catastrophic in an adult yet be expected in that pediatric context. The researchers contend that troponin testing in children needs different benchmarks tailored to each specific condition, rather than one generic reference range applied broadly across all clinical scenarios.

The technical challenges behind building those benchmarks are considerable. Establishing a pediatric reference interval requires recruiting sufficient numbers of healthy children across multiple age bands, from neonates through adolescents, because troponin physiology changes with development. Samples must be analyzed on defined platforms with characterized analytical performance, and statistical methods for partitioning the data by age and sex must be agreed upon in advance. For condition-specific thresholds, the task is harder still: researchers need cohorts of children with each disease, followed long enough to know which troponin values actually predict outcomes that matter, such as reduced heart function, need for intensive care, or late cardiovascular complications. No single laboratory can generate that evidence alone, which is why the survey’s authors frame the problem as one requiring coordinated global action rather than isolated local fixes.

That call for coordination is echoed in the study’s leadership. Dr. Lianna G. Kyriakopoulou, Director of Genome Diagnostics at The Hospital for Sick Children and the University of Toronto in Canada, said the committee was driven by the belief that children deserve diagnostic care built around their biology, not borrowed from adult medicine. To advance precision child health, she said, the field now needs coordinated global action to develop pediatric reference intervals, strengthen clinical guidance, and ensure every child receives results that are accurate, meaningful, and equitable. The framing of equity is significant: laboratories in well-resourced centers may at least be aware of the limitations of adult-derived cutoffs, while facilities with fewer resources may have no way to know their pediatric results rest on uncertain ground.

The survey also highlights a structural gap between the pace of assay development and the pace of pediatric validation. Cardiac troponin assays have become extraordinarily sensitive over the past two decades, capable of detecting injury at concentrations once invisible, and manufacturers have raced to bring high-sensitivity platforms to market. Adult populations, with their large volumes of chest-pain presentations, provide the datasets needed to validate those assays quickly. Children, whose testing volumes are smaller and whose indications are scattered across many rare conditions, do not generate comparable data through routine care. Unless pediatric-specific studies are deliberately funded and designed, the market alone will not close the gap, and laboratories will continue to default to manufacturer-provided adult intervals because those are the only numbers available on the package insert.

For practicing clinicians, the survey’s message is a call for caution and for advocacy. A troponin result in a child should be interpreted with an explicit understanding of what reference interval was applied and how it was derived, and where child-specific data are absent, results should be correlated with imaging, clinical course, and other biomarkers rather than acted upon in isolation. For laboratory directors, the findings argue for transparency about the limitations of current intervals and for participation in the multi-center collaborations that the IFCC committee is promoting. And for funders and professional societies, the study is evidence that pediatric laboratory medicine remains an underbuilt discipline in which even a test as routine as troponin rests, for most of the world’s children, on data borrowed from their parents’ medicine. Closing that gap, the authors suggest, is not a technical luxury but a prerequisite for giving children the same standard of diagnostic certainty that adults have long enjoyed.

Subject of Research: Pediatric cardiac troponin testing and the lack of child-specific reference intervals

Article Title: Mind the child heart gap

Article References: Mind the child heart gap. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: cardiac troponin, pediatrics, reference intervals, laboratory medicine, IFCC, myocarditis, Kawasaki disease, cancer treatment, clinical chemistry, heart injury, diagnostic testing, global survey