A Retrospective Review of Vitamin D Requests in General Paediatric Practice

Background: Vitamin D testing in Paediatric Medicine is carried out mainly in the context of a child at risk of deficiency. Deficiency is diagnosed by directly measuring serum levels of 25-hydroxyvitamin D. Serum levels >50nmol/L are considered normal. Deficiency is considered mild between 25nmol/L-50nmol/L, moderate between 12.5nmol/L – 50nmol/L and severe at <12.5nmol/L. The ranges for defining deficiency were changed between 2011 and 2012 where normal levels were previously between 75nmol/L – 200nmol/L.

Objective: To review vitamin D testing in an Irish General Paediatric Practice.

Methods: A history of all vitamin D tests requested by consultant paediatricians in a large general paediatric practice, servicing a catchment area with a population of 100,000 children over the five-year time-period from 01/07/2011 to 01/07/2017 was collected. Patient charts were reviewed and the indications for testing were identified. Results from testing were also collected. Data was analysed using IBM SPSS Statistics package version 23 for Macintosh.

Results: A total of 361 tests were requested over the five-year study period. Most of the samples analysed were from female patients. The main indications for testing were: established vitamin D deficiency, presenting with bony pain, neurological issues and failure to thrive. The mean age of the sample was 6 years of age. The majority of cohort had vitamin D levels within the normal range.

Conclusion: The reference range currently in use for vitamin D testing is that from 2012. Using current ranges, few children were deemed deficient. Comparably, three times more were deficient when previous ranges were used. Most patients were not deficient on testing. 46% of testing was carried out on a patient with previously established deficiency.