Measurement of Plasma Free Hemoglobin Using the Hemolysis Index of the Mindray BS ‐800

BACKGROUND: The Mindray BS-800 chemistry analyzer (Mindray Bio-Medical Electronics) has a hemolysis index (HI) function and is a candidate method for detecting free hemoglobin (fHb). This study aimed to validate the HI on the Mindray BS-800 for measuring plasma fHb. METHODS: Using EDTA plasma diluted with normal saline, the analyzer measured hemoglobin absorbance at 570 and 605 nm. Results were compared with those of the Harboe method (reference standard), which measures absorbance at 380, 415, and 450 nm. Precision, linearity, limit of detection, interference, reference range, and carryover were also assessed. RESULTS: Replication experiments showed within-run and between-run precision of 0.41%-1.89% and 0.71%-2.10%, respectively. Linearity of fHb measurements was established over 2.3-507.9 mg/dL. The limits of detection and quantitation were 2 and 5 mg/dL, with coefficient of variation values of 16.28% and 6.37%, respectively. No notable interference was observed at triglyceride concentrations up to 520.9 mg/dL; however, bilirubin levels of 14.2-34.7 mg/dL produced a negative bias of up to 15%. The reference range was established at ≤ 23.9 mg/dL. Within the 0-130 mg/dL range, fHb correlated strongly with the Harboe method, yielding the regression equation: HI (mg/dL) = 1.0886 × Harboe (mg/dL) - 0.3071 (r = 0.9967). CONCLUSIONS: Measurement of fHb using the HI on the Mindray BS-800 analyzer provides accurate and reliable results. This approach offers a practical alternative to the Harboe method for routine clinical laboratory use, with improved safety and turnaround time.