Detection of undiagnosed coagulopathies using routine rapid heparin neutralization.
OBJECTIVE
To determine the most frequent clinical causes of a prolonged activated partial thromboplastin time (APTT) result, and to determine whether a new heparin-removal device (the Hepchek, Pall Biomedical, Glen Cove, NY 11542) is capable of efficiently detecting the causes of these values.


METHODS
A combination of chart review and laboratory testing comparing the criterion standard--the heparin chromogenic substrate assay--with the Hepchek. Laboratory investigations were blinded and controlled.


METHODS
Inpatient, acute-care hospital.


METHODS
A total of 1,000 hospital patients with a variety of hemostatic disorders.


METHODS
The extent to which the Hepchek accurately identified the etiology of a prolonged APTT result.


RESULTS
The APTT was prolonged in 25.2% of samples. The presence of heparin in the sample was confirmed by chromogenic assay or by using the Hepchek heparin-removal filter. The presence of heparin was confirmed in 12.8% of all samples and in more than 50% of all abnormal samples. The cause of the abnormal APTT was often unappreciated by the clinician. Bayesian analysis of the Hepchek's ability to diagnose heparin correctly as the cause of the abnormal APTT showed a sensitivity of 100% and specificity of 99.9%.


CONCLUSIONS
Use of the Hepchek in the routine clinical laboratory is an efficient and rapid method of detecting heparin as a cause of isolated prolonged APTT results, and should reduce demands for unwarranted coagulation analyses and inappropriate treatment with blood products.
Department of Laboratory Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
E R
ER
Burns
V
V
Lee
B
B
Wenz
D001499:Bayes Theorem; D001778:Blood Coagulation Disorders / Q000175:diagnosis* / Q000209:etiology; D001780:Blood Coagulation Tests / Q000592:standards*; D003951:Diagnostic Errors; D005374:Filtration / Q000379:methods; D006493:Heparin / Q000097:blood*; D006801:Humans; D010314:Partial Thromboplastin Time