Anti-Xa levels
The secondary outcome sought to evaluate the number of dose changes based off anti-Xa confirmatory, week 1 and monthly levels, once a stable level was attained. Due to the retrospective nature of this study, not all anti-Xa levels were drawn consistently. A confirmatory, week 1, and monthly level were obtained in 45 and 52 patients correctly. Of these, 39/45 (87%) and 44/52 (85%) patients did not have a dose change based on confirmatory and monthly levels, respectively. A total of 33/52 (63%) of patients required a dose change based on the week 1 level. Additionally, the average number of levels drawn were 7.5 per patient, during a 6-12 week treatment period.