Objective: To provide researchers with an unambiguous definition of anaemia using haemoglobin.
Methods: Review of recommendations by expert groups and review of the literature.
Results: This report provides an unambiguous approach to haemoglobin adjustments to define anaemia using international criteria. When determining anaemia using haemoglobin, it is important to account for pregnancy, altitude, cigarette smoking, and possibly ethnicity after removing unlikely values. These haemoglobin adjustments are presented.
Conclusion: Recommendations for defining extreme haemoglobin values and for reporting anaemia and haemoglobin results are provided, and software programs to determine anaemia are described.