Background. — Office-based anticoagulation monitors offer significant advantages in convenience, yet their performance has been inadequately characterized.
Methods.— We characterized the performance of a portable anticoagulation monitoring system with respect to precision and agreement with a reference laboratory. Eighty-five patients from a university outpatient anticoagulation clinic provided 143 whole blood sample pairs for evaluating agreement between the monitor and the laboratory. Fifty-four patients each provided a second pair of samples for assessing the monitor's precision, and 23 pairs of measurements from the reference laboratory were used for assessing the laboratory's precision. Anticoagulation was measured using International Normalized Ratio (INR) values. Agreement between monitor and laboratory was evaluated as the difference between paired measurements. Precision was calculated as the within-patient standard deviation based on paired values.
Results.— Within the range of 2.0 to 3.0 INR units, the monitor yielded values that were up to 0.3 units higher on average than the laboratory values. Within the range of greater than 3.0 to 4.5 INR units, the monitor yielded values that were up to 0.5 units lower on average than the laboratory values. Seventy-five percent of paired monitor and laboratory values were within 0.7 INR units; 90% were within 0.9 units. Within-patient standard deviation was 0.23 units for the monitor and 0.19 units for the laboratory.
Conclusions.— The monitor differed systematically from the laboratory and was moderately less precise. The magnitude of these effects was not great, however, and accuracy was best at around INR = 3.0, the border between low and high therapeutic ranges. The clinic-based monitor is useful for patients requiring frequent surveillance of anticoagulation status.(Arch Intern Med. 1992;152:589-592)
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Purchase Online Access to this article for 24 hours
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Instructions
Thank you for submitting a comment on this article. It will be reviewed by JAMA Internal Medicine editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest* Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 71
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
and access these and other features:
Register Now
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Need assistance?
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.