Figure 1.

Correlation of total, adjusted, and free phenytoin plasma concentrations. (A) Correlation of PHTfree versus PHTtotal/10 for 756 patients is shown. For patients who had multiple phenytoin measurements, only the chronologically first set of PHTfree and PHTtotal/10 measurements is plotted. The solid line is the line of identity, and the dashed line is from linear regression: PHTfree = 0.385 + 1.104 * PHTtotal/10 (R2 = 0.51). The 95% confidence intervals of the intercept is (0.355, 0.415) and for the slope is (1.045,1.163). (B) Correlation of PHTfree versus PHTadj_free is shown using same source of patient data as in (A). The dashed line is from linear regression: PHTfree = 0.223 + 0.980 * PHTadj_free (R2 = 0.62). The 95% confidence intervals of the intercept is (0.129, 0.317) and for the slope is (0.926, 1.034)

Krasowski and Penrod BMC Medical Informatics and Decision Making 2012 12:7   doi:10.1186/1472-6947-12-7
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