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Reference intervals for holotranscobalamin and total vitamin B12 in 6-12-year-old children in Norway: the Health
Martin Frank Strand1, Helle Borgstrøm Hager2, Per Morten Fredriksen3,4
1School of Health Sciences, Kristiania University College, Oslo, Norway.
Insights
This study establishes new vitamin B12 (B12) reference ranges for children aged 6-12. These age-specific vitamin B12 and holotranscobalamin (holoTC) values will improve deficiency diagnosis in pediatric populations.
Area of Science:
- Clinical Chemistry
- Pediatric Endocrinology
- Nutritional Science
Background:
- Vitamin B12 (B12) is crucial for DNA synthesis and neurological health.
- B12 is transported via haptocorrin and transcobalamin, measured as total B12 and holotranscobalamin (holoTC).
- Holotranscobalamin (holoTC) better reflects B12 availability for tissue uptake, but pediatric reference values are scarce.
Purpose of the Study:
- To establish age-specific pediatric reference intervals (RIs) for total B12 and holoTC in healthy school children.
- To provide clinicians with essential data for accurate interpretation of B12 status in children aged 6-12 years.
Main Methods:
- Blood samples from 1320 healthy Norwegian children (ages 6-12) were analyzed.
- Total B12 and holoTC levels were determined using chemiluminescent microparticle immunoassay.
- Age-specific RIs were calculated using the nonparametric method (2.5th and 97.5th percentiles).
Main Results:
- Established 95% RIs for total B12: 295-1066 pmol/L (6-8 years) and 249-879 pmol/L (9-12 years).
- Established 95% RIs for holoTC: ≥56 pmol/L (6-8 years) and ≥37 pmol/L (9-12 years).
Conclusions:
- Age-specific reference intervals for total B12 and holoTC in children aged 6-12 years have been determined.
- These new RIs will enhance the accurate diagnosis and management of vitamin B12 status in pediatric patients.
Abstract:
Vitamin B12 (B12) is essential for DNA synthesis in all cells and for the development and maintenance of a healthy nervous system. B12 is transported in the circulation bound to two carrier proteins, haptocorrin and transcobalamin, measured as the biomarkers total B12 and holotranscobalamin (holoTC). The latter measures the fraction of cobalamin available for tissue uptake and is considered to have a better sensitivity and specificity for diagnosing vitamin deficiency. The concentration of both carrier proteins depends on age, but data on paediatric reference values for holoTC are still sparse. Blood samples were obtained from 1320 healthy school children, mainly Caucasians (age 6-12 years old) in three different municipalities in Norway. The holoTC and total B12 levels were determined by chemiluminescent microparticle immunoassay on the Architect 2000 analyser. Age specific paediatric reference intervals (RIs) were estimated by calculating the 2.5 and 97.5 percentiles by the nonparametric method with corresponding 90% confidence intervals, according to the Clinical and Laboratory Standards Institute C28-A3C guidelines. The 95% RIs for total B12 were 295-1066 pmol/L for children 6-8 years old, and 249-879 pmol/L for children 9-12 years old. Reference intervals for holoTC were ≥56 pmol/L for children 6-8 years old, and ≥37 pmol/L for children 9-12 years old. Age specific RIs will aid clinicians in interpretation of cobalamin results in children aged 6-12 years old.
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