|
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Prothrombin Time and Activated Thromboplastin Time Panel
Test CodePT(LOW ISI) AND PTT
Alias/See Also
Prothrombin Time
Activated Partial Thromboplastin Time
Hematology
Activated Partial Thromboplastin Time
Hematology
Includes
Prothrombin Time
INR
Activated Thromboplastin Time
INR
Activated Thromboplastin Time
Preferred Specimen
Light Blue Top Tube – 3.2% sodium citrate
Transport Temperature
Room temp. Do not place directly on ice.
Specimen Stability
Whole blood, unopened tube, centrifuged or uncentrifuged
PT(LOW ISI):
24 hours stability from time of collection in an unopened tube at room temperature. Storage at refrigerated temps may result in cold activation of factor VII, so any blue tops received in ice may be rejected.
PTT:
Whole Blood
Non-heparinized patients (or patients on heparin that is not unfractionated heparin)
Room temperature/Refrigerated: 6 hours
Patients on unfractionated heparin – deliver to the laboratory ASAP
Room temperature: 1 hour
Patients on direct oral anticoagulants
Room temperature: 2 hours
Aliquoted Plasma
Non-heparinized patients (or patients on heparin that is not unfractionated heparin)
Room temperature: 6 hours
Frozen: 3 months at -20C or 4 months at-70C.
Patients on unfractionated heparin – deliver to the laboratory ASAP
Room temperature: 1 hour
PT(LOW ISI):
24 hours stability from time of collection in an unopened tube at room temperature. Storage at refrigerated temps may result in cold activation of factor VII, so any blue tops received in ice may be rejected.
PTT:
Whole Blood
Non-heparinized patients (or patients on heparin that is not unfractionated heparin)
Room temperature/Refrigerated: 6 hours
Patients on unfractionated heparin – deliver to the laboratory ASAP
Room temperature: 1 hour
Patients on direct oral anticoagulants
Room temperature: 2 hours
Aliquoted Plasma
Non-heparinized patients (or patients on heparin that is not unfractionated heparin)
Room temperature: 6 hours
Frozen: 3 months at -20C or 4 months at-70C.
Patients on unfractionated heparin – deliver to the laboratory ASAP
Room temperature: 1 hour
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Under drawn or overdrawn, clotted and hemolyzed specimens are not acceptable for testing. Patient's receiving anticoagulant therapy may give spurious results.
Methodology
Photo-optical endpoint
Setup Schedule
Daily
Report Available
TAT 1 day
Limitations
Monitor warfarin patients based on the INR value only!
INR therapeutic range for patients on oral anticoagulant therapy is 2.0-3.5.
For patients who are not receiving anticoagulant therapy, the INR of 1.1 or lower is considered normal.
INR therapeutic range for patients on oral anticoagulant therapy is 2.0-3.5.
For patients who are not receiving anticoagulant therapy, the INR of 1.1 or lower is considered normal.
Reference Range
| Test | Reference range | Units |
| PT | 9.8 - 13.3 | Sec |
| INR | ≤1.1 | |
| PTT | 27.9 - 37.0 | Sec |
| Heparinized PTT | 55 - 94 (Therapeutic) | Sec |
Comments:
- For normal patient who are not on anticoagulation, the INR of 1.1 or lower is considered normal.
- Therapeutic range for patients on anticoagulant should be between 2.0-3.5
Performing Laboratory
Test performed in BACL Hematology Labs
Contact West Roxbury: Nolan Raymond 857-203-5980
Alternate contact Joseph A. Manzone JP 857-364-5092
Alternate contact Diane Robert Brockton 774-826-2294
Alternate contact Bhumikaben Patel Bedford 781-687-2976
Last Updated: September 19, 2025
