Prothrombin Time
| Label Mnemonic: | PT |
| Epic code: | LAB320 |
| Downtime form: | Doctor/Provider Orders - Pathology Core and Specialty Care Nursery |
Hemostasis/Thrombosis
6240 RCP
356-3573
6240 RCP
356-3573
Specimen(s):
Plasma More information
Collection Medium:
 |
| Light Blue top tube 1.8 mL (Na Citrate) |
Minimum:
Full draw; 1.8 mL light blue top (mix well). Tube must be at least 90% full.
Rejection Criteria:
Short drawn tube, clot, traumatic tap (excessive hemolysis).
Turn Around
Time:
1 hour (upon receipt in laboratory)
Reference Range:
9-12 seconds
INR Critical Reference Value: greater than 3.9
Methodology:
Optical clot detection.
CPT Code:
85610
See also:
Activated Partial Thromboplastin Time (aPTT), Plasma
Activated Partial Thromboplastin Time (aPTT), Plasma
The INR corresponding to the PT is reported to assist in the monitoring of oral anticoagulants. Must be drawn swiftly with a clean venipuncture (no hematoma). Time drawn must be indicated on requisition. A PT can be performed on a sample if it is kept unopened and uncentrifuged at room temperature to be delivered to lab within 12 hours. A special tube from the lab is necessary if the hematocrit is over 55%.
Prothrombin Time may be performed on the same collection tube as Activated Partial Thromboplastin time (aPTT) and Fibrinogen.
This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).
INR values are intended to be used for patients receiving oral anticoagulant therapy with warfarin. A patient's target INR range may depend on multiple factors, including the clinical indication for anticoagulation and bleeding risk. A standard intensity warfarin therapeutic INR range is 2.0 to 3.0.