Geisinger Medical Laboratories Test Catalog
THROMBIN TIME |
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ORDERING INFORMATION: |
Geisinger Epic Procedure Code: LAB3152 Geisinger Epic ID: 7224 | |
SPECIMEN COLLECTION |
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Specimen type: |
Platelet-free plasma | |
Preferred collection container: |
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Alternate Collection Container: |
Other size blue-top (3.2% sodium citrate) tubes (e.g., 1.8 mL, 4.5 mL)
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Specimen required: |
1 mL aliquot plasma | |
Special notes: |
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SPECIMEN PROCESSING |
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Specimen processing instructions: |
Centrifuge specimen immediately at designated time and speed to obtain platelet-poor plasma (<10,000/µL). Using a plastic pipette, carefully remove plasma from cells, avoiding platelet/buffy layer by leaving a thin layer of plasma on top the cells. The centrifuged plasma should be aliquoted (1 mL per aliquot) into clearly labeled polypropylene tubes. The number of tests ordered will determine the aliquots needed. Check the residual specimen for clot and if present discard sample and redraw specimen. If plasma is icteric, lipemic or hemolyzed a lab comment should be generated to notify staff. Freeze upright in non-thaw freezer. | |
Transport temperature: |
Frozen on dry ice | |
Specimen stability: |
Room temperature (whole blood): 4 hours Room temperature (plasma off cells): 8 hours Frozen (plasma) -20°C: 2 weeks Frozen (plasma) -70°C: 6 months |
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Rejection criteria: |
Clotted specimen. Overfilled or underfilled tubes. Stability limits exceeded. HCT >55. HCT > 55 requires rejection, reorder in LIS, and recollection with proper adjustment of anticoagulant. Indications of thaw in transit are sample on slant in aliquot tube or in lid of tube. These samples will be run but will receive a comment of interpret results with caution as thawing suspected. | |
TEST DETAILS |
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Reference interval: |
14.7 to 19.6 seconds | |
Additional information: |
Anticoagulation Impact on Coagulation Tests | |
CPT code(s): |
85670 | |
Note: The billing party has sole responsibility for CPT coding. Any questions regarding coding should be directed to the payer being billed. The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only. | ||
Test includes: |
Thrombin time | |
Methodology: |
Mechanical clot-based |
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Synonyms: |
TT, thrombin clot time
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Clinical significance: |
The thrombin time is typically prolonged when fibrinogen is less than 100 mg/dL or in the presence of antithrombotic substances including fibrin degradation products, paraproteins, or anticoagulation with either heparin or direct thrombin inhibitors. It can also be prolonged if the fibrinogen is biochemically abnormal or nonfunctional (dysfibrinogenmia).
Thrombin time is typically used in conjunction with fibrinogen activity, fibrinogen antigen, and replitase time assays to determine if the patient has hypofibrinogenemia (low amount of fibrinogen), dysfibrinogenemia, or the plasma contains anticoagulation with either heparin or a direct thrombin inhibitor. Thrombin time is part of the PT/APTT mixing study panel, lupus anticoagulant profile, and thrombosis profile to determine whether anticoagulation is present. |
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Doctoral Director(s:) |
Michelle Grant DO | |
Review Date: | 03/28/2023 |