Table 1.
Tabulation of selective ion monitoring (SIM) attributes and the ions monitored for the respective analytes.
Table 2.
Characteristics of the people with epilepsy (PWE) grouped according to the type of antiepileptic drug.
Figure 1.
Correlation of plasma concentrations of AEDs with their corresponding dried blood spot concentrations.
Plasma concentrations of (top left) carbamazepine (top right) phenytoin and (bottom) valproic acid regressed against their dried blood spot concentrations using Deming regression. The broken line is the line of unity while the continuous line is the line of regression. The (top left) slope is 0.84 (95% CI, 0.76 to 1.00) and the intercept is 1.00 (95% CI, 0.04 to 1.97) for carbamazepine, (top right) slope is 1.61 (95% CI, 1.39 to 1.84) and the intercept is −1.14 (95% CI, −2.40 to 0.12) for phenytoin and (bottom) slope is 1.57 (95% CI, 1.33 to 1.81) and the intercept is 11.91 (95% CI, 5.73 to 18.09) for valproic acid.
Figure 2.
Identity of the plasma concentrations of phenytoin and valproic acid with the theoretical plasma concentrations derived from their dry blood spot concentrations.
Plasma concentrations of (top) phenytoin and (bottom) valproic acid regressed against their theoretical plasma concentrations estimated from dried blood spot concentrations using Deming regression. [Theoretical plasma concentrations = Dried blood spot concentrations/1–Hct×(1–K)], where Hct is hematocrit and K is the RBC/plasma partition ratio. The broken line is the line of unity while the continuous line is the line of regression. The (top left) slope is 1.21 (95% CI, 1.04 to 1.38) and the intercept is −1.04 (95% CI, −2.32 to 0.24) for phenytoin with K = 0.43, (top right) slope is 1.11 (95% CI, 0.95 to 1.27) and the intercept is −1.00 (95% CI, −2.28 to 0.29) for phenytoin with K = 0.29, (bottom left) slope is 1.03 (95% CI, 0.87 to 1.20) and the intercept is 12.16 (95% CI, 5.95 to 18.37) for valproic acid with K = 0.2 and (bottom right) slope is 0.92 (95% CI, 0.77 to 1.07) and the intercept is 12.48 (95% CI, 6.15 to 18.81) for valproic acid with K = 0.042.
Figure 3.
Agreement between the plasma concentrations of carbamazepine and its dried blood spot concentration; and between the plasma concentrations of phenytoin and valproic acid and the theoretical plasma concentrations derived from their dried blood spot concentrations.
Bland Altman plots for plasma concentrations of (top) carbamazepine, (middle left) phenytoin, K = 0.43, (middle right) phenytoin, K = 0.29, (bottom left) valproic acid, K = 0.20 and (bottom right) valproic acid, K = 0.042. The broken lines represent the 95% CI (±1.96 SD) and the continuous line is the mean.