Wittenmeier E, Paumen Y, Mildenberger P, et al. - Precision conferred by non‐invasive haemoglobin measurement using absolute values to be the sole basis for the treatment of pre‐operative anemia is insufficient. However, it is possibly capable of serving as a screening test, indexing ‘anemia’ with high sensitivity when values remain under prespecified cut‐off values. As per previous data, true anaemia can be detected by non‐invasive haemoglobin cut‐off values (146 g.l⁻¹ for women and 152 g.l⁻¹ for men) with 99% sensitivity. In elective surgical patients, verification of an index test with these prespecified cut‐off values was done by prospective measurement of non‐invasive and invasive haemoglobin preoperatively. This demonstrated an estimated sensitivity (95%CI) of 98.9% (94.1–99.9%) in women and 96.4% (91.0–99.0%) in men among 809 patients. Consequently, Invasive blood tests were saved in 9% of female and 28% of male patients. A lower non‐invasive haemoglobin cut‐off value (138 g.l−1) in female patients would save 28% of invasive blood tests with a sensitivity of 95%. Despite a very high sensitivity, the index test using prespecified cut‐off values just failed to reach the target sensitivity to identify true anemia. However, with respect to blood‐sparing effects, they suggest using index test as possibly useful in men, while an index test with a lower cut‐off (132 g.l−1) could be more clinically relevant in women.