The measurement of circulating Haemoglobin A1C (glycated haemoglobin; Hba1c) is a good proxy of the mean plasma glucose concentration over a period of the past 2 months. Haemoglobin A1C levels are commonly used as a screening test for diabetes diagnosis and monitoring. Using freshly collected blood samples, circulating levels of Hba1c can be accurately measured by Boronate affinity high performance liquid chromatography (HPLC). However, it is currently unclear if this method can measure levels of Hba1c accurately using frozen hemolysates. Hba1c prepared hemolysates have previously been collected from ALSPAC mums at various clinics (FOM1, FOM2, FOM3 and FOM4). This proposal is for a pilot study to test the feasibility of measuring Hba1c using frozen Hba1c prepared hemolysates. This project will enable the assessment of whether Hba1c can be measured in frozen Hba1c hemolysates. If this is feasible, Hba1c levels of mums in ALSPAC can be measured and will be useful for future research linked to different health outcomes such as diabetes and cancer.