Distinguishability of blood at different phases of hemolysis by a multiwavelength laser diode based low-cost, table-top photoacoustic system

Hemolysis, the breakdown of red blood cells (RBCs), releases hemoglobin (Hb) into plasma, impairing gas exchange and causing oxidative stress. Hb converted to methemoglobin (mHb), a non-oxygen-binding derivative, further worsens the clinical condition. Current diagnostic methods are invasive or lack real-time capabilities for accurately assessing degree and phases of hemolysis. This study introduces a novel approach utilizing photoacoustics (PA). A low-cost, laser diode based PA system with 447, 638, and 905 nm illumination was developed to investigate the distinguishability of lysed blood at different phases [RBCs in Hb solution (intermediate phase) and RBCs in mHb solution (final phase)] across various equivalent-hematocrit (eqHCT) levels and degrees of lysis. Later, a two-step artificial neural network model accurately classified the hemolysis phase (sensitivity = 1.00 and specificity = 1.00) and estimated eqHCT and lysis degree with 1.14% and 3.17% error, respectively, for the intermediate phase and 0.67% and 1.34% error for the final phase.