Prothrombin with INR and Partial Thromboplastin Times
Test code
CPT code(s)*
Test resources
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Details
The information below details the components of this test. For overall setup schedule, see Performing lab & setup schedule.
Included components
Test code | Test name | Orderable separately | Setup schedule |
|---|---|---|---|
| 763 | Partial Thromboplastin Time, Activated | Yes | Set up: Daily (Day shift or Night shift); Report available: 1 day |
| 8847 | Prothrombin Time with INR | Yes | Set up: Daily (Day shift or Night shift); Report available: 1 day |
Methodology
Photo-optical Clot Detection
Alternative name(s)
APTT,PTT,PT
Specimen requirements | |
|---|---|
| Patient preparation | None Specified |
| Preferred specimen(s) | One full unopened 3.2% sodium citrate (light blue-top) tube |
| Alternative specimen(s) | 1 mL frozen plasma |
| Minimum volume | 0.5 mL frozen plasma |
| Collection instructions | Unopened light blue-top tube: Correct ratio of blood to citrate is critical. Do not overfill or underfill collection tube. Mix by inversion 4 times. For non-heparinized patients, maintain specimen at room temperature. Do not uncap. Stable 24 hours at room temperature. Platelet-poor plasma: Centrifuge light blue-top tube 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcl). Freeze immediately and ship on dry ice. Whole blood: The tubes should be at 100% +/- 10% fill volume in order to obtain the correct ratio. |
| Transport container | 3.2% sodium citrate (light blue-top) tube |
| Transport temperature | Room temperature |
| Specimen stability | Unopened light blue-top tube Room temperature: 24 hours Refrigerated: Unacceptable Frozen: Unacceptable Separated platelet-poor plasma Room temperature: Unacceptable Refrigerated: Unacceptable Frozen: 14 days |
| Reject criteria | Gross hemolysis • Grossly lipemic • Improper blood to citrate ratio • Clotted • High hematocrit • Improper blood collection |
Reference Range(s)
Prothrombin Time with INR
INR
| ≤3 months | Not established |
| >3 months | |
| Reference range | 0.9-1.1 |
| Moderate-intensity Warfarin therapy | 2.0-3.0 |
| Higher-intensity Warfarin therapy | 3.0-4.0 |
| ≤3 months | Not established |
| >3 months | 9.0-11.5 sec |
Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (9.0-11.5 seconds) is generally applicable down to approximately 3 months of age with younger patients having a slightly higher upper limit by several seconds. Warfarin Therapeutic INR Range: 2.0-3.0
Partial Thromboplastin Time, Activated
| ≤6 months | Not established |
| >6 months | 23-32 sec |
Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (23-32 seconds) is generally applicable down to approximately 6 months of age with younger patients having a slightly higher upper limit by several seconds.
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NOTE: The codes listed in the table are not orderable Test Codes
Result code | Result name | LOINC code | Component name |
|---|---|---|---|
| 30039900 | PT | 5902-2 | Coagulation |
| 30040200 | INR | 6301-6 | Coagulation |
| 30051900 | PARTIAL THROMBOPLASTIN TIME, ACTIVATED | 14979-9 | Coagulation |
Performing laboratory
| Quest Diagnostics LLC |
| 200 Forest Street, 3rd Floor, Suite B |
| Marlborough, MA 01752-3023 |
Setup schedule
Information not provided in New England (MA, ME, RI, VT, Northern CT, NH) –Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
*The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.
This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.
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