College of American Pathologists
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Prothrombin self-testing:where the lab comes in

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August 2002
Karen Southwick

Pathologists are not directly involved with prothrombin time self-testing, but they are aware of its value.

Two members of the CAP Coagulation Resource Committee, Tim Hayes, MD, and Doug Triplett, MD, agree that self-monitoring of prothrombin times can be a viable alternative for some patients. But, they say, a physician must oversee the process.

"There are patients who would rather try to manage it themselves, instead of going to a clinic or a lab for monitoring," says Dr. Triplett, a professor of pathology at Indiana University School of Medicine. "That’s a call for the physician who’s managing the patient. He has to sit down and discuss the positives and negatives of home monitoring."

Patients must be able to understand the process. "The No. 1 criteria for making this successful is the commitment of the patient," Dr. Triplett says. "Does the patient understand the consequences of overdosing or underdosing?" The second important criteria is to have a clinic or physician’s office with an infrastructure for helping the patient manage anticoagulation therapy.

Says Dr. Hayes, "It has to be the right patient, the right physician, and the right system" for home testing to work. By the right system, he means a handheld device that is somewhat error-proof and ongoing communication with the physician.

Drs. Hayes and Triplett say the hospital laboratory plays a peripheral role in home monitoring, especially if a hospital-affiliated anticoagulation clinic is managing the process. "The role for the lab is to assist the physicians in understanding the risks of testing at home," says Dr. Hayes, of the Maine Medical Center, Portland. "Ideally, the lab would be perceived as a resource."

Dr. Hayes says it’s much easier for a central laboratory to coordinate with a warfarin clinic than with 20 or 30 physician offices. The ideal arrangement would be for the home testing to be performed in connection with a centralized clinic that has a laboratory as backup. "You don’t want it to get too fragmented," he says. "If there’s a problem with a patient’s monitor, who do they go to? How do you even know there’s a problem with a device used only once a week?" Quality oversight must be maintained, he adds.

Dr. Triplett concurs. "This is something that can work," he says, particularly because the devices on the market make it relatively simple. "Physicians and patients who are involved with self-testing are very comfortable with it now."