Usefulness of non-invasive spectrophotometric haemoglobin estimation for detecting low haemoglobin levels when compared with a standard laboratory assay for preoperative assessment

This study is approved by the Tasmanian Human Ethics Committee, Australia and was registered prospectively in the Australian and New Zealand Clinical Trials Registry (http://www.ANZCTR.org.au/ ACTRN12611001256965) and the World Health Organization Clinical Trials Registry (http://apps.who.int/trialsearch/trial.aspx?trialid=ACTRN12611001256965).