Reliability of a spot check non-invasive hemoglobin monitoring (SpHb) of the Masimo RAD-67™ and the HemoCue® for anemia screening
Authors: Baulig W , Eichenberger U , Theusinger O.M. 
Published: November 2022

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® Hb 201+ System (HemoCue AB, Ängelholm, 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 (HbLab), the HemoCue® Hb 201+ System (HbHemocue) and by Pulse Co-Oximetry using the Masimo Rad-67 (SpHb) with the rainbow® DCI®-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 HbLab. In 20 patients, the HbHemocue, and in 34 patients, the SpHb detected anemia. Linear correlation and mean bias (limits of agreement, LOA) for HbHemocue and HbLab were r = 0.969 and -1.08 (+6.44/-8.60) g/L, and for SpHb and HbLab r = 0.61 and +1.76 (+26.92/-23.4) g/L. Sensitivity/specificity of the HbHemocue 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%, 75.0/95.2/% 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 : HbHemocue and HbLab show a strong linear correlation and a good agreement, while linear correlation of SpHb and HbLab is moderate and agreement poor. For both devices, anemia detection is moderate, but the positive prediction value for anemia is much better with the HbHemocue. Both devices reliably detected non-anemic patients.

Glossary : CO = carbon monoxide ; PPV = positive predicted value ; NPV = negative predicted value ; HbLab = hemoglobin determined by the laboratory ; HbHemocue = hemoglobin determined by the HemoCue device ; SpHb = hemoglobin determined by the Masimo-RAD67 device ; LOA = limits of agreement ; LOS = length of stay ; POC = point of care ; SpO2 = arterial hemoglobin ; PR = pulse rate ; PI = perfusion index ; PVI = plethysmography variability index ; SpCO = carboxyhemoglobin ; SpMet = methemoglobin ; LED = Light Emitting Diodes ; HiCN = hemiglobincyanide ; SLS = Sodium Lauryl Sulphate ; BMI = body mass index ; BT = body temperature ; WHO = World Health Organization ; IQR = interquartile range ; MAP = mean arterial pressure ; HF = heart frequency ; SD = standard deviation

Key point Summary :
– Question : Is Hb measurement of the Masimo Rad-67 and of the HemoCue reliable?
– Findings : Non-anemic patients are reliably detected with the Masimo Rad-67. Of the 303 patients examined, HbLab detected twenty-one patients (12 male and 9 female) with mild or moderate anemia. The Hbhemocue showed anemia in 20 patients, while the SpHb identified 34 patients as anemic. HbHemocue and HbLab showed a strong linear correlation and a good agreement, while linear correlation of SpHb and HbLab was moderate and agreement poor. For both devices, anemia detection is moderate, but the positive prediction value for anemia is much better with the HbHemocue. Both devices reliably detected non-anemic patients.
– Meaning : With both devices, non-anemic patients are reliably recognized, while anemia detection is moderate. However, the prediction for the presence of anemia is much better with the Hbhemocue.