Groundbreaking Study Points to Crucial Gap in Children’s Clinical Testing

By LabMedica International staff writers
Posted on 03 May 2022

Image: Study demonstrates significant inconsistencies with pediatric reference interval (Photo courtesy of Unsplash)

To correctly interpret clinical test results for pediatric patients, physicians must evaluate results within the context of reference intervals - the range of normal test values appropriate for the age, stage of development, ethnicity, and gender of a child. Now, a groundbreaking study has demonstrated significant inconsistencies with pediatric reference intervals, which are essential to high quality pediatric medical testing.

The study completed by laboratory medicine experts at the American Association for Clinical Chemistry (AACC, Washington, DC, USA) identifies some of the most pressing issues in this area, thereby paving the way for the medical community to develop more reliable pediatric reference intervals and vastly improve children’s medical care. The pediatric reference intervals in use today are highly inconsistent for a broad range of common clinical laboratory tests, a problem that puts children at risk for inappropriate or even harmful medical care. For example, imprecise reference intervals can lead to a physician missing that a child has a serious medical condition and failing to administer treatment in time.

With this in mind, a team of AACC scientists analyzed the reference intervals for several common and important pediatric tests. These reference intervals included those for free thyroxine, thyrotropin, ferritin, hemoglobin, and IGF-1, all of which are crucial for early identification and treatment of various disorders that impact pediatric cognitive and physical development; cystatin C, which is used to predict end-stage kidney disease in children; estradiol (a form of estrogen); and testosterone. The researchers examined the numerous reference intervals for each of these tests that are published in the scientific literature, as well as those developed and used by individual clinical labs.

From this, the team found that many of these pediatric reference intervals are inappropriate for assessing a child’s health or monitoring treatment. The reference intervals for free thyroxine, thyrotropin, ferritin, cystatin C, estradiol, and testosterone were particularly inconsistent, especially during developmental stages where children undergo rapid biochemical changes. As just one example, some pediatric reference intervals for free thyroxine and thyrotropin fail to capture the surge in these two hormones that occurs in the first few days of life, which could lead to incorrect diagnoses of thyroid diseases in newborns. Inconsistencies such as this are due, in part, to the high variability in the age groups used to represent certain life stages during pediatric reference interval development - a finding that is essential to improving these reference intervals in the future.

“There is a need to correctly describe the biochemistry of child development, as well as to identify strategies to develop accurate and consistent pediatric reference intervals for improved pediatric care,” said Hubert W. Vesper, PhD, an AACC member and director of clinical standardization programs at CDC, who led the team of AACC scientists. “Continued communication and collaboration between clinicians and their laboratory colleagues ensures appropriate clinical test interpretation and patient assessment and remains essential to effective implementation of common pediatric reference intervals.”

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