Diagnosis and Treatment Archive
Abnormal Prothrombin Time
 
What is a prothrombin time test?

Prothrombin time (PT) measures the blood's ability to clot properly. A prothrombin time test uses a control sample to establish a normal rate for how fast blood should clot. A patient's blood is compared to that sample, and abnormal results are stated as prolonged beyond control. This means how many seconds longer it took the patient's blood to clot than the sample. For example, let's say the normal range is 10 -13 seconds. If a patient's prothrombin time level was 3 seconds beyond control, that means it took 16 seconds for his/her blood to clot.

Click here for another, simpler explanation of prothrombin time.

 

What does it mean to have an abnormal prothrombin time?

Click here for information on normal prothrombin time values and what abnormal results may indicate.

Note: For the purposes of this project, we will consider prothrombin time in seconds, not in INR.

Prothrombin time is tested as part of a routine liver panel, which also includes:

 

Possible causes

Possible causes include: