Geisinger Medical Laboratories Test Catalog
APTT |
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ORDERING INFORMATION: |
Geisinger Epic Procedure Code: LAB1772 Geisinger Epic ID: 7231 | |
SPECIMEN COLLECTION |
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Specimen type: |
Platelet-poor 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 | |
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: |
Plasma (on or off cells): Room temperature Plasma off cells: Frozen on dry ice |
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Specimen stability: |
Room temperature: 4 hours (no heparin therapy), 1 hour (heparin therapy) Frozen (plasma) -20°C: 2 weeks Frozen (plasma) -70°C: 6 months |
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Rejection criteria: |
Clotted, hemolyzed, improperly filled tubes, improper anticoagulant ratio (HCT >55% and citrate not adjusted), refrigerated specimens, or stability exceeded.
Note: Specimen suspected of thawing in transport, indicated by slant in aliquot or specimen in lid of tube, will have testing performed, and the comment “interpret results with caution as thawing suspected” added to results. |
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TEST DETAILS |
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Reference interval: |
21-38 seconds | |
Critical values/courtesy alerts: |
Greater than 120 seconds | |
Additional information: |
Anticoagulation Impact on Coagulation Tests | |
CPT code(s): |
85730 | |
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: |
APTT | |
Methodology: |
Mechanical clot-based |
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Synonyms: |
PTT, Activated Partial Thromboplastin Time
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Clinical significance: |
Screening test used to assess the intrinsic and common clotting pathways. Prolongation of the APTT may be associated with bleeding and could indicate one or more deficiencies of plasma factors XII, XI, IX, X, V, II, or fibrinogen (only if less than 100 mg/dL), and/or a possible inhibitor (factor dependent or lupus anticoagulant) as well as a vitamin K deficiency (from dietary or intestinal reabsorption disorders). Diseases often associated with prolonged APTT include liver failure, lupus anticoagulant, and disseminated intravascular coagulopathy (DIC).
Medications may also prolong the APTT including heparin, direct Xa inhibitors, and direct thrombin inhibitors. A heparin nomogram using the APTT is available from the Geisinger pharmacy, but it is not recommended for heparin monitoring; instead, an unfractionated or low molecular weight heparin level should be utilized. |
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Doctoral Director(s:) |
Michelle Grant DO | |
Review Date: | 03/28/2023 |
Performing Locations
Geisinger Wyoming Valley Medical Center
Geisinger Shamokin Area Community Hospital
Geisinger Community Medical Center
Geisinger Medical Center Muncy