Quantitative liquid chromatography-tandem mass spectrometric analysis of 11-dehydrothromboxane B2 and creatinine in urine

• • The method achieves linearity for 11dH-TXB2 from 0.1 to 50 ng/mL (r² = 0.99656) and for creatinine from 10 to 5000 ng/mL (r² = 0.99950), enabling quantification across clinically relevant ranges without dilution. • • Quality control accuracies range from 85.83% to 113.21% with RSDs ≤ 9.71%, and standard recoveries of 85–110%, satisfying regulatory acceptance criteria for bioanalytical method validation. • • Organic phase extraction replaces solid-phase extraction, reducing sample preparation time and cost while maintaining analytical performance, facilitating high-throughput clinical testing. • • Simultaneous detection of 11dH-TXB2 and creatinine in a single run allows immediate normalization to urinary creatinine, eliminating separate assays and improving diagnostic workflow for aspirin resistance assessment.