Evaluation of point-of-care activated partial thromboplastin time testing by comparison to laboratory-based assay for control of intravenous heparin.
BACKGROUND
Patients on intravenous heparin require regular activated partial thromboplastin time monitoring. Laboratory-based activated partial thromboplastin time assays necessitate a delay between blood sampling and dose adjustment. Point-of-care testing could permit immediate dose adjustments, potentially enabling tighter control of anticoagulation.


OBJECTIVE
To assess equivalence of activated partial thromboplastin time measured by conventional laboratory assay and by a novel proprietary point-of-care testing system (Hemochron Response, ITC, Thoratec Corporation, Edison, NJ) among surgical ward patients on intravenous heparin.


METHODS
A total of 39 blood samples from patients on intravenous heparin were tested with both laboratory and point-of-care assays. Assay equivalence was assessed by Bland-Altman analysis. Results. Point-of-care measurements exceeded laboratory activated partial thromboplastin time by a mean of 15 seconds (standard deviation 19). In 19 cases (49%), the point-of-care measurement would have resulted in different heparin dosing from the laboratory activated partial thromboplastin time.


CONCLUSIONS
The Hemochron Response system is not sufficiently accurate for routine ward use compared with laboratory activated partial thromboplastin time assays.
Douglas
Alexander D
AD
Departments of Vascular Surgery, Haematology, and Intensive Care, Oxford Radcliffe Hospitals NHS Trust, Oxford, United Kingdom. sandyddouglas@gmail.com
Jefferis
Jo
J
Sharma
Rishi
R
Parker
Rachel
R
Handa
Ashok
A
Chantler
Jonathan
J
D019411:Clinical Laboratory Techniques / Q000592:standards*; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D010314:Partial Thromboplastin Time / Q000592:standards*; D019095:Point-of-Care Systems / Q000592:standards*; D011183:Postoperative Complications / Q000097:blood / Q000188:drug therapy; D012015:Reference Standards; D015203:Reproducibility of Results; D013503:Surgery Department, Hospital; D014656:Vascular Surgical Procedures
D006493:Heparin