Biomarkers · Chemical
Prothrombin Time
- Primary unit
- sec
- LOINC codes
- 5902-2
- Tests that measure Prothrombin Time
- Labcorp 5, Quest Diagnostics 3
Ranges
Each lab publishes a reference range for the population groups it tests, usually the middle 95% of results. These intervals describe that population, not an optimal or healthy target. How ranges differ
Quest Diagnostics, Prothrombin with INR and Partial Thromboplastin Times 4914
| Population | Interval |
|---|---|
| INR, ≤3 months | Not established |
| INR, Reference range | 0.9-1.1 |
| INR, Moderate-intensity Warfarin therapy | 2.0-3.0 |
| INR, Higher-intensity Warfarin therapy | 3.0-4.0 |
| >3 months | Not stated |
| PT, ≤3 months | Not established |
| PT, >3 months | 9.0-11.5 sec |
| Partial Thromboplastin Time, Activated, ≤6 months | Not established |
| Partial Thromboplastin Time, Activated, >6 months | 23-32 sec |
Quest Diagnostics, Prothrombin Time with INR 8847
| Population | Interval |
|---|---|
| INR, ≤3 months | Not established |
| INR, Reference range | 0.9-1.1 |
| INR, Moderate-intensity Warfarin therapy | 2.0-3.0 |
| INR, Higher-intensity Warfarin therapy | 3.0-4.0 |
| >3 months | Not stated |
| PT, ≤3 months | Not established |
| PT, >3 months | 9.0-11.5 sec |
Tests
Check the catalog code, specimen, method and preparation for every test that measures Prothrombin Time. Select up to five tests to compare them side by side.
Labcorp 5 tests
Panels that include this biomarker
Prothrombin Time (PT) 005199
2 analytes · Plasma · Fasting not stated · Turnaround Within 1 day
Labcorp catalog pageMethod and collection
- Method
- Prothrombin time reagent containing thromboplastin and calcium chloride is mixed with the patient plasma and the time to clot formation is measured photo-optically. The calcium chloride overcomes the citrate anticoagulant and allows the tissue factor in the thromboplastin to initiate coagulation. The prolongation of the clotting time correlates with the degree of deficiency or inhibition of the extrinsic pathway factors.
- Collection
- Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
- Reference notes
- See table. Age | Range13-15 Prothrombin Time (PT) 1 day | 14.4−16.4 sec 3 days | 13.5−16.4 sec 1 to 11 m | 11.5−15.3 sec 1 to 5 y | 12.1–14.5 sec 6 to 10 y | 11.7−15.1 sec 11 to 16 y | 12.7−16.1 sec >16 y | 12.2 –14.9 sec International Normalized Ratio (INR) 0 to 1 m | 0.9−1.4 >1 m | 0.9−1.2
Prothrombin Time (PT) (Serial Monitor) 485199
2 analytes · Specimen not stated · Fasting not stated · Turnaround Within 1 day
Prothrombin Time (PT) and Partial Thromboplastin Time (PTT) 020321
3 analytes · Plasma · Fasting not stated · Turnaround Within 1 day
Labcorp catalog pageMethod and collection
- Preparation
- Draw specimen one hour before next dose of heparin if heparin is being given by intermittent injection. Do not draw from an arm with a heparin lock or heparinized catheter.
- Collection
- Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
- Reference notes
- See table. Age | Range6-8 Activated Partial Thromboplastin Time (aPTT) 1 d | 29–38 sec 3 d | 25−36 sec 1 to 11 m | 30−39 sec 1 to 5 y | 29−37 sec 6 to 10 y | 27–37 sec 11 to 16 y | 25–34 sec >16y | 23–34 sec Prothrombin Time (PT) 1 d | 14.4−16.4 sec 3 d | 13.5−16.4 sec 1 to 11 m | 11.5−15.3 sec 1 to 5 y | 12.1–14.5 sec 6 to 10 y | 11.7−15.1 sec 11 to 16 y | 12.7–16.1 sec >16y | 12.2–14.9 sec International Normalized Ratio (INR) 0 to 1 m | 0.9−1.4 >1 m | 0.9−1.2
Drug-Induced Liver Injury Profile 010045
6 analytes · Serum · Fasting not stated · Turnaround Within 1 day
Labcorp catalog pageMethod and collection
- Method
- See individual tests.
- Collection
- Serum or plasma: Separate serum or plasma from cells within 45 minutes of collection. PT with INR blood: Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube. When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Disseminated Intravascular Coagulation (DIC) Profile 116012
7 analytes · Plasma · Fasting not stated · Turnaround 2 - 3 days
Labcorp catalog pageMethod and collection
- Method
- See individual tests.
- Preparation
- None
- Collection
- Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge and carefully remove the plasma using a plastic transfer pipette, being careful not to disturb the cells. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Quest Diagnostics 3 tests
Single-analyte tests
Prothrombin Time with INR 8847
One full unopened 3.2% sodium citrate (light blue-top) tube · Fasting not stated · Turnaround Set up: Daily (Day shift and Night shift); Report available: 2 days
Quest Diagnostics catalog pageMethod and collection
- Method
- Photo-Optical Clot Detection
- Collection
- A completely filled tube is necessary because the correct ratio of blood to citrate is critical (9:1). Mix by gentle inversion 3-4 times. Do not uncap.
Prothrombin with INR and Partial Thromboplastin Times 4914
One full unopened 3.2% sodium citrate (light blue-top) tube · Fasting not stated
Quest Diagnostics catalog pageMethod and collection
- Method
- Photo-optical Clot Detection
- Collection
- 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.
Panels that include this biomarker
Mixing Study 8922
3 analytes · Plasma · Fasting not stated
Quest Diagnostics catalog pageMethod and collection
- Method
- Clot Detection
- Collection
- Please submit a separate, frozen vial for each special coagulation assay ordered. Draw blood in a light blue-top tube containing 3.2% sodium citrate, mix gently by inverting 3-4 times. Centrifuge 15 minutes at 1500 g within one hour 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(s). Freeze immediately and transport on dry ice.
- Reference notes
- Prothrombin Time | 9.0-11.5 sec Immediate PT-Mix | ≤11.5 sec PTT-LA, Baseline | ≤40 sec Immediate PTT-LA Mix | See Laboratory Report Incubated PTT-LA Mix | See Laboratory Report
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5 tests: codes, specimens, methods, preparation and reference intervals.
Quest Diagnostics test catalog
3 tests: codes, specimens, methods, preparation and reference intervals.
LOINC 5902-2
Regenstrief Institute codes that identify the same result across labs.
Search ClinicalTrials.gov for Prothrombin Time
Registered studies that measure Prothrombin Time, on the U.S. National Library of Medicine registry.
Verify these ranges and sources
We compile this page from named laboratory catalogs, guidelines and studies. Labs calculate reference intervals from the people they test, for one assay method and one population group, so an interval describes that population rather than an optimal target.
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