Nutritional Biochemistry in Inborn Errors of Immunity: A Single Centre Audit

Introduction Children with inborn errors of immunity (IEIs) are at risk of nutritional deficiencies secondary to underlying condition- and treatment-related impacts. However, only one study has assessed the nutrition status of paediatric patients across a range of IEI disorders within a clinical setting, and no studies have assessed this in an Australian context. This study aimed to explore nutritional status in patients with IEIs in a regional tertiary centre in New South Wales, Australia, using nutritional biochemistry. Method A retrospective chart audit was conducted of all paediatric patients with an IEI managed by the John Hunter Children’s Hospital Paediatric Immunology team over a 5-year period (2019–2024). Demographic data were extracted, including age, sex, type of IEI, and treatment. Nutritional biochemistry data were informed by our previous systematic review, including iron studies, haemoglobin, vitamin D, vitamin B12, folate, vitamin A, vitamin K, calcium, selenium, zinc, and albumin. Biomarkers were coded as within or outside normal range, and data were analysed descriptively. Results Over the 5 years, a total of 29 patients and 82 pathology tests were included in the biochemistry audit. Frequent nutritional biochemistry tests included iron studies (n = 77), albumin (n = 60), and haemoglobin (n = 54). Biochemistry frequently outside of normative ranges included transferring (53%), ferritin (47%), haemoglobin (37%), B12 (27%), and calcium (24%). Conclusion A range of nutritional biomarkers were frequently outside of normal ranges for children with IEIs. Routine testing of nutritional biochemistry should be considered for children with IEIs. Future clinical practice guidelines are needed to guide the types of nutritional biochemistry tests and their frequency.