What proportion of vancomycin trough levels are drawn too early?: frequency and impact on clinical actions.

Am J Clin Pathol. 2012 Mar;137(3):472-8

Authors: Morrison AP, Melanson SE, Carty MG, Bates DW, Szumita PM, Tanasijevic MJ

Abstract
Vancomycin trough levels are recommended to predict vancomycin efficacy, and inaccurate levels may lead to inappropriate clinical actions. However, the frequency of timing errors and associated clinical impact is unknown. We retrospectively analyzed vancomycin levels (n = 2,597) measured during 13 months at a large academic medical center. Of the specimens, 41.3% were drawn too early. These samples yielded significantly higher average ± SD vancomycin concentrations than correctly timed samples (22.1 ± 11.7 mg/L vs 15.5 mg/L ± 8.6 mg/L; P < .001), and, consequently, clinicians were more likely to decrease, discontinue, or hold a patient's vancomycin dose (25.6% vs 21.4%; P < .02) or repeat the vancomycin level (29.2% vs 20.0%; P < .001). A substantial proportion of specimens collected to assess vancomycin efficacy were drawn too early, leading to overestimation of patients' true trough level and possible underdosing of vancomycin or a high rate of repeat tests for vancomycin.

PMID: 22338061 [PubMed - indexed for MEDLINE]

Myelodysplastic syndromes.

Am J Clin Pathol. 2009 Aug;132(2):290-305

Authors: Orazi A, Czader MB

Session 4 of the 2007 Workshop of the Society for Hematopathology/European Association for Haematopathology was devoted to myelodysplastic syndromes (MDSs). Submitted cases highlighted important issues and difficulties in relation to the diagnosis and classification of MDS. Much of the discussion focused on the correlation, or lack of it, between morphologic examination and other diagnostic techniques, cytogenetics in particular. The cases included examples of isolated del(5q) chromosomal abnormality, including the "classical" 5q- syndrome and other myeloid neoplasms. Other cytogenetic abnormalities in MDSs and the role of cytogenetics in diagnosing MDSs were addressed. Particularly challenging is the correct identification of fibrotic subtypes of MDSs and their separation from subsets of acute myeloid leukemia with myelofibrosis such as acute panmyelosis with myelofibrosis. The association and eventual relation of MDSs (hypoplastic in particular) with aplastic anemia, paroxysmal nocturnal hemoglobinuria, and other nonneoplastic disorders were illustrated. Novel cytogenetic and molecular genetic approaches are likely to revolutionize the classification of MDSs. However, it is unlikely that these new techniques will be capable, on their own, of adequately stratifying patients for treatment purposes. At least for the foreseeable future, the diagnosis of MDS requires integration of morphologic, immunophenotypic, and genetic features in the light of patient history and clinical manifestations.

PMID: 19605823 [PubMed - indexed for MEDLINE]