Reliability of a spot check non-invasive hemoglobin monitoring (SpHb) of the Masimo RAD-67™ and the HemoCue® for anemia screening

Background : To test the reliability of the spot check Masimo Rad-67 (Masimo Corp., Irvine, CA, USA) as part of a preoperative anemia screening, hemoglobin measurements were compared to those of the HemoCue (R) Hb 201+ System (HemoCue AB, Angelhohn, Sweden) and the standard laboratory measurement. Methods : During preoperative evaluation of patients scheduled for elective orthopedic surgery hemoglobin concentration was simultaneously determined by standard laboratory analysis (Hb(Lab)), the HemoCue (R) Hb 201+ System (Hb(Hemocue)) and by Pulse Co-Oxirnetry using the Masimo Rad-67 (SpHb) with the rainbow (R) DCI (R)-mini Sensor (Masimo Corp., Irvine, CA, USA). Linear correlation, agreement (Bland-Altman analysis), sensitivity/specificity and positive/negative prediction values (PPV/NPV) for anemic hemoglobin values were determined. P-values less than 0.05 were considered statistically significant. Results : 303 patients were analyzed. Twenty-one patients (12 male and 9 female) had mild or moderate anemia, detected by Hb(Lab). In 20 patients, the Hb(Hemocue) and in 34 patients, the SpHb detected anemia. Linear correlation and mean bias (limits of agreement, LOA) for Hb(Hemocue) and Hb(Lab) were r = 0.969 and -1.08 (+6.44/-8.60) g/L, and for SpHb and Hb(Lab) r = 0.61 and +1.76 (+26.92/-23.4) g/L. Sensitivity/specificity of the Hb(Hemocue) to detect anemia in all, male and female patients were 85.0/99.3%, 75.0/100/% and 88.9/98.9/% with a PPV/NPV of 89.5/98.9%, 100/98.0% and 80.0/99.3%, respectively. Sensitivity/specificity of SpHb to detect anemia for all, male and female patients were 71.4%, 93.3%, 75.0/95.21% and 66.7/91.1%. with a PPV/NPV for all, male and female patients of 44.1/97.8%, 56.3/97.9% and 33.3/97.7%, respectively. Conclusions : Hb(Hemocue) and Hb(Lab) show a strong linear correlation and a good agreement, while linear correlation of SpHb and Hb(Lab) is moderate and agreement poor. For both devices, anemia detection is moderate, but the positive prediction value for anemia is much better with the Hb(Hemocue) Both devices reliably detected non-anemic patients.