Development of a Low-Cost Spectrometer for Hemolysis Detection in Emergency Blood Gas Samples

BACKGROUND: Hemolysis is a major cause of sample rejection in blood gas analysis. We aimed to develop a low-cost spectrometer for hemolysis detection in emergency laboratories. METHODS: The spectrometer was developed using a complementary metal-oxide-semiconductor (CMOS) sensor and DVD-ROM grating. We evaluated the linearity, precision, and interference resistance of the instrument in accordance with CLSI and China National Accreditation Service for Conformity Assessment (CNAS) guidelines. In 51 clinical blood gas samples subjected to mechanically simulated hemolysis, the correlation between absorbance at 540 nm (A540 nm) and the hemolysis index (H index) determined by the Cobas c701 biochemical analyzer was evaluated. We utilized the hemolysis absorbance value that causes a maximum ±10% deviation in potassium (K+) and calcium ion (Ca2+) results as a reference to establish the rejection criteria for hemolysis in blood gas samples. RESULTS: The detection range of the spectrometer spanned 0.160< A540 nm <2.67, exhibiting a highly significant correlation with the H index (P < 0.01). The between-run coefficient of variation (CV) for the device was below 5%, while the within-laboratory CV remained below 10%. At interfering substance levels of 8.0 mg/dL (136.8 μmol/L) for unconjugated bilirubin, 13.3 mg/dL (226.7 μmol/L) for conjugated bilirubin, and 431.4 mg/dL (4.87 mmol/L) for triglycerides, detection bias stayed within 10%. Hemolysis significantly altered pH, partial pressure of oxygen (pO2), K+, and Ca2+ (P < 0.05). By calculating the bias caused by hemolysis on the test results, rejection criteria were established: A540nm >0.671 hemolysis will affect K+ results and A540nm >0.960 hemolysis will affect Ca2+ results. CONCLUSION: This low-cost spectrometer enables reliable pre-analysis hemolysis detection, improving accuracy in blood gas testing.