Pediatric reference intervals in routine laboratory practice

By Maj. Matthew Raines, MD, DABP I

n order to establish a diagnosis of wellness or disease, checklists – like that of the College of American Pathologists’ (CAP) All Common checklist for the chemistry section – require all patient results to be reported with reference ranges. This ensures that healthcare providers can review results compared to the (usually) normal population, as measured on the same analytical platform.

The process for establishing or adopting reference

ranges for adult populations is well-documented elsewhere. Pediatric reference ranges, on the other hand, are more complicated. Pediatric and adult physiology differ, and results can vary with age, analyte, and sometimes sex. Instead of establishing a single reference range per analyte (as with adults), up to 18 total ranges may be established for a single analyte when considering incremental age ranges (up to 18) and sex. However, many laboratories do not receive enough pediatric samples within each age interval to statistically power each reference range. As part of standard medical practice, clinicians want to prevent multiple unnecessary

Maj. Matthew Raines, MD, DABP, director and pathologist in the U.S. Air Force.

searching the literature for each analyte, one by one, and comparing the analytical platform to that employed in one’s own lab can be laborious. To address this issue, the American Association for Clinical Chemistry (AACC) published Pediatric Reference Intervals (previously Pediatric Reference Ranges),1

which provides tables of analytes with

pediatric reference ranges, platforms utilized, and study references. In an attempt to provide the most relevant information to providers at Joint Base Elmendorf- Richardson Hospital (JBER Hospital), we queried our laboratory information system (LIS) to create a report identifying the tests most frequently ordered for pediatric patients at our institution. I also reviewed LIS test files to identify which pediatric reference ranges were reported with lab results. The next task was to compile missing reference ranges. Our laboratory utilizes a Siemens Vista for chemistry and a Stago STA Compact for coagulation studies. A search of reagent inserts and the published literature revealed few, if any, pediatric reference ranges established on these models. The above-mentioned text, however, provided extensive tables of reference ranges performed on precursor instruments (Dimension RxL and STA-R, respectively). A review of manufacturer reagent inserts was performed to insure uniformity between previous and current platforms. Following these steps, I consolidated previously

In pediatrics, test results can vary with age, analyte and sometimes sex.

blood draws from children, further adding to the complexity of determining pediatric reference ranges.

When it is not feasible to establish reference

ranges in-house due to limitations in the number of samples, it may be acceptable to adopt reference ranges from studies performed by the manufacturer or otherwise published in the literature. But

6 CLR 2020-2021 • MLO •

established reference ranges into a more provider- friendly and accessible chart form, based on commonly ordered tests at our institution. This handout for providers includes a comprehensive chemistry panel, a coagulation panel, a lipid panel, and an iron panel. The handout was distributed to clinics and published in our lab guide. A useful (and even more verifiable) future step for the laboratory industry would be the publication of reference ranges by large-volume pediatric facilities on the most current analytical platforms.

(Please see Pediatric reference tables on page 8)

REFERENCES: 1. Wong E, Brugnara C, Straseski, Kellogg M, Adeli K. Pediatric Reference Intervals. New York: Elsevier; 2011.

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