Blood glucose is ideally measured in the laboratory, with methods that use glucose oxidase, hexokinase or glucose dehydrogenase reactions. In practice, it is measured using point-of-care (POC) glucose meters because they provide a quick result with a small sample of blood. These meters measure a current generated by an enzyme reaction (glucose oxidase or glucose dehydrogenase) that is proportional to the amount of glucose in the blood sample. They were originally developed to identify normoglycemia and hyperglycemia in adult patients. They are not accurate at detecting low glucose levels. Therefore they cannot be used to accurately diagnose hypoglycemia, although they can be used for screening. Newer methods to monitor blood glucose are being developed, and include CGMS (continuous glucose monitoring system), microdialysis, non-invasive methods that rely on spectroscopy, and use of a biosensor that detects glucose-binding-protein through the neonatal skin.