Relationship between serum TXB₂ and VerifyNow Aspirin measurements during different aspirin regimens. The figure depicts the relationship between serum TXB₂ and VerifyNow Aspirin measurements performed in 15 patients during different aspirin regimens. The dotted line depicts the best fitting of the experimental data. The logarithmic relation between the 2 variables is as follows: y = 40ln(x) + 378 (R² = 0.43, n = 75). Each point in the graph represents the median value for each aspirin regimen, the horizontal and vertical bars indicate the corresponding IQR (25-75th percentile). EC indicates enteric-coated aspirin; od, once daily; and bid, twice daily.