Study presented at ADLM 2026 provides local data to improve pediatric laboratory interpretation and reduce unnecessary testing.
A research team has established age-specific reference intervals for complete blood count (CBC) tests in healthy Vietnamese children to improve diagnostic accuracy. The study, presented at the Association for Diagnostics & Laboratory Medicine (ADLM) 2026 meeting, marks the first time such data has been developed specifically for this population.
CBC is one of the most frequently ordered laboratory tests in children, commonly used to evaluate anemia, infections, inflammatory conditions, and platelet abnormalities. Historically, laboratories in Vietnam often used reference intervals—the expected range of values for a test—derived from non-Vietnamese populations. Because blood parameters vary across populations and change during growth, researchers sought to establish local, age-appropriate standards.
“This means that a result considered normal for an infant may not be normal for an adolescent, and vice versa,” says Duyen Nguyen, lead investigator of Vietnam National Children’s Hospital in Hanoi, in a release.
Age and Sex Influence on Blood Parameters
Between 2024 and 2025, Nguyen and colleagues recruited 3,982 healthy children aged 0-19 through community- and school-based health screening programs across multiple regions of Vietnam. The team analyzed peripheral blood samples using an automated hematology system to establish the reference intervals.
The investigators found that age has a major influence on normal blood count values. Total white blood cell upper reference limits declined from 15.17 x 10⁹/L in infants less than 6 months of age to 10.71 x 10⁹/L in adolescents aged 12-19. While neutrophil counts increased progressively with age, platelet counts decreased gradually across childhood.
Red blood cell parameters, including red blood cell count, hemoglobin, and hematocrit, increased throughout childhood. Sex-specific differences emerged only after puberty. In adolescents aged 12-19, hemoglobin upper reference limits were 171 g/L in males and 150 g/L in females.
Improving Clinical Decision-Making
The establishment of these local intervals is intended to prevent the misclassification of healthy children. Using data from different populations can lead to results being flagged as abnormal, triggering unnecessary follow-up investigations.
“Our findings are primarily intended to improve laboratory interpretation,” says Nguyen in a release. “More appropriate pediatric reference intervals may reduce the likelihood of classifying healthy children as abnormal simply because the reference values were derived from a different population. This can support more informed clinical decision-making and reduce unnecessary follow-up investigations.”
The research team expects these data to serve as a national resource, supporting more consistent interpretation of hematologic results for pediatric patients throughout the country.
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