Table 4.

Performance evaluation of calculated unbound concentrations as a predictor of measured unbound concentrations using bias, 95% limits of agreement, and associated confidence intervals, as determined by Bland-Altman plots^a

Antibiotic	Bias (%)	95% CI of bias	95% limit of agreement	95% CI (lower limit)	95% CI (upper limit)
Piperacillin	0.43	−6.6–7.4	−34.7, 39.6	−41.7–−27.7	33.6–46.6
Ampicillin	−5.08	−15.5–5.4	−22.2, 12.0	−32.7–−11.7	1.5–22.5
Benzylpenicillin	−25.00	−57.4–7.4	−86.97, 37.0	−119.3–−54.6	4.6–69.4
Meropenem	12.08	6.6–17.6	−10.2, 34.4	−15.7–−4.7	28.8–39.9
Ceftriaxone	−83.30	−117.2–−49.4	−168.5, 1.9	−202.4–−134.6	−32.0–35.8
Cefazolin	9.33	−41.1–59.7	−55.7, 74.4	−106.1–−5.3	24.0–124.8
Flucloxacillin	−56.80	−130.1–16.5	−197.2, 83.6	−270.5–−123.9	10.3–156.9

^aData are presented as percentages relative to percentage protein binding. CI, confidence interval.