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HelpTest Code PT Prothrombin Time - INR
Synonyms/Keywords
Protime, PT, INR, CSPT, CS PT, Code Stroke PT, Code Stroke Protime
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Whole Blood, Plasma | 3.2% Citrated Blue Top Tube (BTT) | 1.0 mL Plasma | 0.6 mL Plasma | ||
| CoaguChek XS = Whole Blood Fingerstick | Sterile (no additive) non-anticoagulated clear top tube | 45 uL | 45 uL |
Collection/Processing Instructions
- Citrated Blue Top Tube (BTT) must be drawn to the fill line.
- Completely invert tube three or four times to mix. Do Not Shake.
- Centrifuge tube at 3000 rpm for 10 minutes or Stat Spin for 3 minutes at 8500 rpm with the brake OFF as soon as possible after collection.
- Perform testing within 24 hours of specimen collection or transfer plasma to polypropylene tube with plastic pipette for storage within two hours of collection.
If sending to another testing location: When APTT and Protime-INR are ordered together send only one frozen, plasma aliquot (1mL) for both tests, labeled with the APTT and Protime-INR specimen labels. Separate Citrated Blue Top Tube (BTT) or room temperature plasma is not needed
CoaguChek XS: Samples must be tested immediately after collection.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood or Plasma | Ambient | 24 Hours |
| Plasma | Frozen (-18C) | 2 Weeks |
| Frozen (-70C) | 6 Months | |
| Frozen thawed | 2 Hours | |
| CoaguChek XS Whole Blood Fingerstick | Ambient | Must be tested immediately |
Rejection Criteria
| Reject at gross hemolysis |
|---|
| Specimens filled below the fill line |
| Clotted |
| Frozen whole blood |
| Known IV fluid or Hickman line fluid contamination |
| Specimens with abnormal results that have a Hct >55% that have not had the citrate anticoagulant adjusted |
| Specimens stored on ice or refrigerated (2-8 deg Celsius) |
| CoaguChek XS testing: serum or plasma |
Test Information
Hemolysis does not interfere with sample analysis, however it may be an indicator of clotting factor activation prior to testing. Clinical correlation with results recommended.
Interpretations
Recommended therapeutic ranges for oral anticoagulant therapy:
- Prophylaxis; venous thromboemb./high risk surgery: INR = 2.0-3.0.
- Prophylaxis; venous thromboemb. hip surgery: INR = 2.0-3.0.
- Treatment of deep vein thrombosis or pulmonary embolism: INR = 2.0-3.0.
- To prevent systemic emboli with atrial fib., valvular heart disease, tissue heart valves or AMI: INR = 2.0-3.0.
- For mechanical prosthetic heart valves, recurrent systemic embolism: INR = 2.0-3.5.
Refer to Care Management-Anticoagulation Services.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| All Performing Sites | 0.9-1.1 (INR) |
| See Critical value List for list of current critical values | |
Marshfield Labs Performing Department
Marshfield Labs Hematology
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Beaver Dam | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| *Bloomer | Monday through Friday | Less than 2 hours | Amperometrically |
| Chippewa Falls | Monday through Friday | Less than 2 hours | Optical Clot Detection/Sysmex CA-620 |
| *Colby/Abbotsford | Monday through Friday | Less than 2 hours | Amperometrically |
| *Cornell | Monday through Friday | Less than 2 hours | Amperometrically |
| *Cumberland | Monday through Friday | Less than 2 hours | Amperometrically |
| Weston | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| *Eagle River | Monday through Friday | Less than 2 hours | Amperometrically |
| Eau Claire | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| Park Falls | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| *Hayward | Monday through Friday | Less than 2 hours | Amperometrically |
| Ladysmith Medical Center | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CA-620 |
| *Lake Hallie | Monday through Friday | Less than 2 hours | Amperometrically |
| Lakeview Medical Center | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| Marshfield | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| *Menomonie | Monday through Friday | Less than 2 hours | Amperometrically |
| *Merrill | Monday through Saturday | Less than 2 hours | Amperometrically |
| Minocqua | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
| *Mosinee | Monday through Friday | Less than 2 hours | Amperometrically |
| Neillsville | Monday through Sunday | Less than 2 hours | Optical Clot Detection/Sysmex CS-2500 |
|
*Oakwood |
Monday through Friday | Less than 2 hours | Amperometrically |
| Phillips | Monday through Friday | Less than 2 hours | Amperometrically |
| *Rhinelander | Monday through Friday | Less than 2 hours | Amperometrically |
| Stevens Point | Monday through Friday | Less than 2 hours | Optical Clot Detection/Sysmex CA-660 |
| *Wausau | Monday through Sunday | Less than 2 hours | Amperometrically |
| Wisconsin Rapids | Monday through Friday | Less than 2 hours | Optical Clot Detection/Sysmex CA-660 |
| *Wittenberg | Monday through Friday | Less than 2 hours | Amperometrically |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 85610 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 85610 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Prothrombin Time - INR |