Point of Care Diagnostics for Iron Deficiency in pre-menopausal women undergoing surgery - testing the efficacy of saliva sampling versus blood sampling

Saliva ferritin levels will be collected from all participants using a fasted, morning saliva sample during the patient's admission prior to surgery. The saliva collection kits are commercially available kits from Salimetrics. Kits will be provided to patients in their hospital cubicle by research coordinators/ research nurses. Participants will use the ‘passive drool method’ to provide their sample which is anticipated to take up to five minutes. They will be shown an instructional video (approx four minutes in length) and instructed to allow saliva to collect in their mouth. They will then lean forward and allow the saliva to drool into the saliva collection kit. Participants will be instructed not to spit or force the saliva out of their mouth to avoid foaming. A total of 0.5mL minimum is required for analysis. Following collection of the sample, research staff will visually inspect the sample to confirm that the minimum sample was required and to check that there is an acceptable amount of foam in the sample. The sample will then be immediately transported and stored in a -80 degree Celsius freezer in the Barwon Health laboratory. Samples will be collected intermittently or at the end of the study, as arranged with the CSIRO. Samples will be further processed (e.g. clarified by centrifugation) and analysed for ferritin levels by an established method. The assay kit will be the Human Ferritin ELISA Kit (ab108837) supplied by Abcam. The same cut offs for serum ferritin levels will be used to classify patients as either iron deficient, normal or elevated with regard to their salivary levels of ferritin (Iron Deficiency: 220 µg/L).