Can Non-Invasive Spectrophotometric Hemoglobin Replace Laboratory Hemoglobin Concentrations for Preoperative Anemia Screening? A Diagnostic Test Accuracy Study

Abstract

Preoperative assessment of hemoglobin concentration in blood is important to diagnose anemia. The primary aim of this prospective diagnostic test accuracy study was to monitor non-invasive spectrophotometric hemoglobin (SpHb, g/dL) concentrations among adults prior to elective surgery and to investigate the correlation and agreement of SpHb with laboratory hemoglobin (Hb, g/dl). A secondary aim was to identify the anemia cut-off values for SpHb based on the World Health Organization (WHO) definitions for anemia. This study included 151 consecutive patients (age ≥ 18 year) presenting for preoperative evaluation prior to scheduled elective general or orthopedic surgery. Results identified the mean ± SD of SpHb at 11.43 ± 2.01 g/dL, which underestimated the mean laboratory Hb (12.64 ± 2.29 g/dL, p < 0.001). A bias mean difference (SpHb–Hb) of −1.21 g/dL, with a SD of 1.76, was reported. This bias (SpHb–Hb) was inversely correlated with the mean Hb concentrations. A positive correlation existed between SpHb and Hb, with a good degree of reliability and a significant Intra Class Correlation (ICC). SpHb diagnosed anemia in 32.3% and 60.3% of males and females, respectively. The SpHb cut-off values to identify anemia were 11.3 and 10.2 g/dL for males and females, respectively, with a sensitivity of 83.3% for males and only 62.9% for females. The specificity for males and females were 81% and 91.3%, respectively. SpHb sensitivity allows for anemia diagnosis among males, but not females. However, the specificity allows SpHb to rule out anemia for both.

Comparing Non-Invasive Spectrophotometry to Hematology Analysis for Hemoglobin Measurements in Sickle Cell Disease Patients

“…This was evident in the current study in which the recorded values of the PI were low, with a mean ± SD at 2.52 ± 1.7. This PI value is lower than that reported by other studies among patients with a normal hemoglobin structure [10,19]. In Alwabari et al's study, the PI values were higher among patients with a normal hemoglobin structure and normal peripheral circulation.…”

“…These results represent part two of our study, with this part focusing on patients suffering from sickle cell disease characterized by an abnormal hemoglobin structure. The first part of this study focused on patients with a normal hemoglobin structure and was recently published [19].…”

“…The information presented here concerns the second part of this study. The first part of this study focused only on patients with normal hemoglobin concentrations and was published recently [19]. The current research represents the second part of this study and focuses on a different population of patients, namely, patients with abnormal hemoglobin as a result of sickle cell anemia.…”