Age-adjusted cut-offs in D-dimer testing for PE cause concern

(HealthDay)—D-dimer unit type should be clarified and laboratories interested in implementing age-adjusted D-dimer (AADD) cut-offs should use only specific D-dimer assays that have been adequately assessed in clinical studies, according to an Ideas and Opinions piece published online Dec. 27 in the Annals of Internal Medicine.

Andrew J. Goodwin, M.D., from the University of Vermont Medical Center in Burlington, and colleagues discuss concerns relating to AADD cut-off use for diagnosing patients with suspected pulmonary embolism.

The authors note that widespread implementation of AADD cut-offs poses concerns, including lack of standardized D-dimer unit reporting, limitation of D-dimer testing, and lack of defined strategies for laboratories to adopt these cut-offs. Although the College of American Pathologists and Clinical Laboratory and Standards Institute require D-dimer results to be reported with a unit type and unit of magnitude, an array of D-dimer units are used, resulting in confusion and possibly in clinical error. Physicians should also be aware about the limitation of the AADD clinical studies, with most studies using only a few commercially available D-dimer kits. For example, the most frequently quoted study used only five commercial, high-sensitivity, quantitative D-dimer assays. The lack of understanding of D-dimer units and assay performance can put patient safety at risk.

"Collaboration among professional organizations, regulatory bodies, and manufacturers may be necessary to improve the overall safety of AADD testing to exclude pulmonary embolism," the authors write.

Two authors disclosed financial ties to Haematologic Technologies and Werfen Instrumentation Laboratory.

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