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Iron deficiency anaemia (IDA) is a frequent sequelae amongst children with chronic gastrointestinal (GI) disorders including inflammatory bowel disease (IBD). 1 Oral iron is often ineffective or poorly tolerated due to malabsorption and gastrointestinal side effects, making intravenous (IV) iron therapy the more suitable option.2 Ferric carboxymaltose and iron sucrose are commonly used IV preparations. Hypophosphataemia is a recognised adverse effect of Ferric carboxymaltose classified by the Electronic Medicines Compendium (EMC) as common (1–10%).3 The Medicines and Healthcare products Regulatory Agency (MHRA) advises checking and monitoring serum phosphate in patients at risk of hypophosphataemia or receiving repeated doses of IV ferric carboxymaltose, particularly in those with pre-existing risk factors such as malabsorption or chronic inflammatory GI conditions.4 Hypophosphataemia can cause myalgia, bone pain, confusion, seizures, arrhythmias and can be life threatening if severe.5In our tertiary paediatric gastroenterology unit, the current practice is to use ferric carboxymaltose if IV iron is required. This audit aimed to evaluate the use of IV Iron for patients attending in our paediatric gastroenterology unit and compare current phosphate monitoring practices against national guidance.A retrospective review was performed of paediatric patients who received ferric carboxymaltose over a six-month period. Inclusion criteria: < 16 years, IDA diagnosis, GI diagnosis. Data collected included haemoglobin, mean corpuscular volume, haematocrit, serum iron, ferritin, and phosphate measured within seven days pre-infusion and fourteen days post-infusion. Dosing followed standard weight-based protocols, and infusion-related adverse events were documented.Twenty-five children received IV iron during the audit period. IBD accounted for 60% of cases, with the remainder having other identifiable GI conditions such as short bowel syndrome or intestinal failure. 100% (25/25) patients received Ferric carboxymaltose. No acute infusion-related reactions occurred. Twelve patients (48%) had phosphate measured pre-infusion, eight (32%) post-infusion, and seven (28%) at both time points. All of these blood tests had been checked for reasons other than phosphate monitoring related to ferric carboxymaltose administration. Mean haemoglobin increased by 15 g/L, while mean phosphate decreased by 0.05 mmol/L. One child developed mild hypophosphataemia (0.84 mmol/L) requiring IV phosphate replacement. A further child developed moderate hypophosphataemia (0.6 mmol/L) requiring oral phosphate replacement; a pre-infusion phosphate was unavailable resulting in an inability to assess causality.Ferric carboxymaltose was effective and appeared well tolerated for the treatment of IDA in children with GI disorders. However, phosphate monitoring was inconsistent and often not aligned with MHRA or published paediatric guidance. Action points arising from this audit include: improving staff education and awareness of the potential side effects of IV iron administration, creation of a standardised electrolyte monitoring protocol for ferric carboxymaltose to improve safety and consistency of patient care. International collaboration work is ongoing with another tertiary paediatric GI centre as this other centre primarily uses Iron Sucrose as first line treatment for paediatric patients with GI disorders. This collaborative project will explore differences in phosphate changes, treatment efficacy, and clinical outcomes for patients, ultimately informing optimal intravenous iron selection for this patient group.References Guagnozzi D, Severi C, Iezzi ML, et al. Iron deficiency anaemia in inflammatory bowel disease: pathogenesis, diagnosis, and treatment. Nutrients 2021;13(1):238. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC8760031/Short MW, Domagalski JE. Iron deficiency anaemia: evaluation and management. Am Fam Physician. 2013;87(2):98–104. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6689119/Vifor Pharma UK Limited. Ferinject 50 mg iron/mL dispersion for injection/infusion – Summary of Product Characteristics (SmPC). Electronic Medicines Compendium (emc). Last updated 19 Jan 2024 [cited 2025 Nov 03]. Available from: https://www.medicines.org.uk/emc/product/5910/smpcMedicines and Healthcare products Regulatory Agency. Ferric carboxymaltose (Ferinject®): risk of symptomatic hypophosphataemia leading to osteomalacia and fractures. Drug Saf Update. 2020;13(8):2. Available from: https://www.gov.uk/drug-safety-update/ferric-carboxymaltose-ferinject-risk-of-symptomatic-hypophosphataemia-leading-to-osteomalacia-and-fracturesKaur J, Castro D. Hypophosphatemia. [Updated 2024 Feb 12]. In: Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493172/