Prothrombin Time
Label Mnemonic: PT
Epic Lab Code: LAB320
Downtime Form: A-1a General Laboratory Requisition
Hemostasis/Thrombosis
6240 RCP
356-3573
Specimen(s):
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
Comments:
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 24 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).
Methodology:
Optical clot detection.
CPT Code:
85610