What Is a Heparin Test?

A heparin test is a lab test to check on levels of unfractionated heparin in the blood to determine how well a patient responds to therapy. Heparin is an anticoagulant medication a doctor may recommend for a person with abnormal clotting to reduce the risk of stroke, heart attack, and other complications associated with blood clots. While the patient takes the medication, he will need periodic testing to monitor his health. If the heparin gets too concentrated, it could create risks.

When a doctor identifies abnormal clotting activity in a patient, she can prescribe heparin injections. The heparin will reduce the level of clotting factors in the blood. In addition to being prescribed for patients, it is also used to make linings for certain kinds of medical devices, to limit the changes of clotting in intravenous lines and other medical equipment. The body naturally produces this compound to control clotting. The introduction of more to a patient's system will treat a clotting disorder and reduce the risk of complications.

In a heparin test, a doctor collects a blood sample around six hours after a heparin injection. A lab technician will determine how much unfractionated heparin is present, and this information will help the doctor determine if the dosage needs adjusting. It is also useful for long term monitoring of patients on this medication, or for the evaluation of patients with heparin resistance. These patients may not respond to therapy as expected, and the heparin test can provide important information about why.

This test is not very invasive, although some people find the process of taking a blood sample uncomfortable. Results usually come back quickly, and the doctor can discuss them if there are any specific questions or concerns. Patients may want to know how the test influences the decision to increase or decrease the heparin dosage and can also discuss the implications of long term heparin therapy.

Most labs are capable of performing a heparin test. Hospital labs can do the test and return results very quickly so doctors can constantly adjust patient care protocols in response to the most recent information. The lab will usually provide a reference of index values so the doctor can compare the patient's results to the standard values. This is important, as different labs can return slightly different results on a heparin test, and the doctor needs to know whether the patient falls within normal range, not just the absolute measurements on heparin levels.