American journal of clinical pathology
-
Am. J. Clin. Pathol. · Dec 2010
Comparative StudyPerformance characteristics of six intact parathyroid hormone assays.
The aim of this study was to evaluate the performance characteristics of 6 intact parathyroid hormone assays: Access 2 (Beckman Coulter, Fullerton, CA), ARCHITECT i2000(SR) (Abbott Diagnostics, Abbott Park, IL), ADVIA Centaur (Siemens Healthcare Diagnostics, Deerfield, IL), Modular E170 (Roche Diagnostics, Indianapolis, IN), IMMULITE 2000 (Siemens Healthcare Diagnostics), and LIAISON (DiaSorin, Stillwater, MN). Sample collection tubes and storage conditions were compared. Imprecision studies were performed using commercial quality control materials. ⋯ The maximum deviation from the target recovery for linearity ranged from 5.0% to 82.2%. Bland-Altman plots demonstrated percentage biases ranging from -36.3% to 24.4%. The lower limit of the reference interval was not influenced by vitamin D status, whereas the upper reference limit was affected.
-
Am. J. Clin. Pathol. · Dec 2010
Evaluation of heparin assay for coagulation management in newborns undergoing ECMO.
The objective was to identify the usefulness of heparin level by anti-factor Xa (anti-Xa) assay vs activated partial thromboplastin time (PTT) or activated clotting time (ACT) in neonates undergoing extracorporeal membrane oxygenation (ECMO). A retrospective record review of 21 patients in the neonatal intensive care unit (mean ECMO initiation age, 2 days; range, 0-4 days; male/female ratio, 1:1) undergoing ECMO from 2006 to 2008 was performed. ⋯ Pearson correlation coefficients between heparin levels and PTT (-0.903 to 0.984), PTT less than 40 seconds after correction using PTT-heparinase (-0.903 to 1.000), and ACT (-0.951 to 0.891) in this patient population were widely variable. Inconsistency of PTT and ACT therapeutic ranges corresponding to heparin levels of 0.3 to 0.6 U/mL prompts a multifactorial approach to ECMO management because no single laboratory test can be used to determine appropriate anticoagulation management.