title: Usefulness of non-invasive spectrophotometric haemoglobin estimation for detecting low haemoglobin levels when compared with a standard laboratory assay for preoperative assessment.
abstract: BACKGROUND
  Delay in diagnosis of anaemia during preoperative assessment poses logistic problems, leading to multiple clinic visits, inadequate preoperative management, and unnecessary delay of surgery. Therefore, we tested an instant spectrophotometric haemoglobin (SpHb) measurement technique to facilitate this assessment.
  
  
  METHODS
  We evaluated portable instant SpHb vs standard laboratory screening of anaemia between March 2012 and December 2013. Paired Hb measurements were performed on 726 patients using SpHb (Pronto-7, Masimo Corporation, Irvine, CA, USA) and Hb measured on the same day using an automated analyser. The results were obtained from a group of 638 patients from the pre-anaesthetic clinic with expected normal Hb values, and 88 patients from the oncology clinic with known low Hb.
  
  
  RESULTS
  Median (range) SpHb was 129.5 (67-171) compared with 136 g litre(-1) (63-178) Hb measured using the automated system. Identifying Hb below a threshold of 130 g litre(-1) for males had a high sensitivity (93%), while identifying a threshold of 120 g litre(-1) for females had lower sensitivity (75%). The specificity for males (77%) and females (81%) was similar. Mean measurement bias and agreement: tolerability interval ratio was -8.1 g litre(-1) and 2.78 for men and -3.1 g litre(-1) and 2.44 for women.
  
  
  CONCLUSIONS
  SpHb was sensitive as a preliminary screening tool for detecting true low Hb values in males, but less sensitive in females. Instant SpHb measurement may enable prompt routine preoperative anaemia management, but its precision was lower than expected.
  
  
  BACKGROUND
  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).
authors.affiliation: Department of Medicine and Haematology, Launceston General Hospital, Launceston, Australia School of Health Sciences, University of Tasmania, Hobart, Australia Menzies Research Institute, University of Tasmania, Hobart, Australia khalafallah@dhhs.tas.gov.au.
authors.forename: A A
authors.initials: AA
authors.lastname: Khalafallah
authors.affiliation: Department of Anaesthesia, Launceston General Hospital, Launceston, Australia.
authors.forename: C R
authors.initials: CR
authors.lastname: Chilvers
authors.affiliation: Department of Medicine and Haematology, Launceston General Hospital, Launceston, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Medical School, Monash University, Melbourne, Australia.
authors.forename: C M
authors.initials: CM
authors.lastname: Chilvers
authors.affiliation: Department of Medicine and Haematology, Launceston General Hospital, Launceston, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Sexton
authors.affiliation: Department of Anaesthesia, Launceston General Hospital, Launceston, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Vialle
authors.affiliation: School of Health Sciences, University of Tasmania, Hobart, Australia.
authors.forename: I K
authors.initials: IK
authors.lastname: Robertson
mesh_terms: D000368:Aged; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D011446:Prospective Studies; D013053:Spectrophotometry / Q000379:methods*
chemical_list: D006454:Hemoglobins
keywords: laboratory Hb; pre-anaesthetic clinic; preoperative anaemia; preoperative screening; spectrophotometric Hb