| Hemoglobin Home | Clinical Accuracy | Reimbursement | Hemoglobin & Anemia |
| The Value of Continuously-Trended Hemoglobin | Rainbow Technology Overview |
Proven Accuracy Compared to Laboratory Devices
Noninvasive and continuous hemoglobin with Masimo Rainbow SET provides accurate measurements that can be trended over time.
- > In 492 comparisons of SpHb readings with invasive hemoglobin (tHb) measurements taken at the same time and analyzed by a laboratory CO-Oximeter, SpHb had a correlation of 0.90, a standard deviation of 0.95 g/dL, and 96% of SpHb values were >1.5g/dL from the laboratory value in the critical anemic range below 12 g/dL.1
- > Comparisons to laboratory devices other than a CO-Oximeter may result in greater differences.
CLINICAL VARIABILITY OF HEMOGLOBIN MEASUREMENTS
The clinical measurement of total hemoglobin has inherent variability. CO-Oximeter and point-of-care (POC) devices that are commonly used to measure hemoglobin have been shown to vary up to ±1.2 and ±1.3 g/dL, respectively. Additionally, there are a variety of physiologic and methodologic factors that can significantly influence hemoglobin levels in the body. Physiologic factors such as the blood source (venous or arterial), site and time of blood draws, and patient body postition are recognized in the clinical literature to add variability to hemoglobin levels.
Blood draw techniques such as "pushing out" blood during a fingertip capillary draw and blood-mixing errors can have an additional variability impact on hemoglobin measurement.
Table 1. Intradevice comparison of Hb measurement of the same blood sample on two identical devices
| Intradevice Comparison | Brand A | Brand B | Brand C | Brand D | Brand E |
| Mean (g/dL) Standard deviation (g/dL) |
-0.8 0.3 |
-0.3 0.2 |
-0.4 0.9 |
0.0 0.1 |
0.4 1.2 |
Table 2. Variation in Hb measurement across 31 CO-Oximeter devices
| Comparison | Level 1 | Level 2 | Level 3 | Level 4 |
| Mean Hb Value of Control (g/dL) | 5.4 | 8.4 | 13.8 | 17.4 |
| Standard deviation: all devices (g/dL) | 0.3 | 0.3 | 0.4 | 0.5 |
| Range/Level (g/dL) | 5.0-5.4 | 8.0-8.6 | 13.3-14.2 | 17.1-17.7 |
Table 3. Factors Affecting Hemoglobin Accuracy in POC Devices
| False low Hb concentration readings: | False high Hb concentration readings: |
| Finger squeezed, or milked, which dilutes the blood sample with interstitial fluid | Blood sample clots before cuvette filled, causing the sample to be concentrated |
| Site wet from alcohol solution when punctured - dilutes sample | Microcuvette not completely filled because of poor blood flow from a shallow stick |
| Microcuvette contains air which lowers the concentration of RBC's in the sample |
Total Hemoglobin Measurements:Accuracy of Laboratory Devices and Impact of Physiologic Variation
Accuracy of Noninvasive and Continuous Hemoglobin Measurement by Pulse CO-Oximetry 1 Masimo FDA Submission Data
