UW Hospital and Clinics Lab Test Directory
| Test Name: |
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PTT
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| Test Code(s): |
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APTT / PTT
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| CPT Code(s): |
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85730
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| Methodology: |
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Mechanical Clot Detection
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| Days Performed: |
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Daily, 24 hours.
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| Turnaround Time: |
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Stat: 1 hour.
Routine: 4 hours.
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Specimen Requirements
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| Specimen: |
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Blood
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| Collection Instructions: |
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The venipuncture MUST be atraumatic to avoid hemolysis and contamination with tissue factors and platelets. Tube MUST be allowed to fill up to "fill" line indicated on tube. Do not spin or open.
If unable to collect 1.8 ml tube (pediatrics only) please call Core Coagulation Lab at 263-9617 or Special Coagulation Lab at 263-5005 for alternate tube and instructions.
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| Collection Container: |
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Preferred: Light blue top (3.2% NaCitrate)
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| Collection Volume: |
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Preferred: 3.5 mL
Pediatrics: 1.8 mL
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| Sample Analyzed: |
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Plasma
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| Volume Required: |
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Preferred: 0.5 mL
Pediatrics: 0.5 mL
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| Specimen Processing: |
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Centrifuge specimen to yield platelet poor plasma (platelet count should be less than 10 K/uL). Separate plasma and transfer to plastic tube or vial. Freeze plasma at -20°C or below.
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| Specimen Transport: |
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Transport whole blood specimen at room temperature to UWHC Core Laboratory (B4/220) within 4 hours of collection. Otherwise, transport frozen plasma aliquot on dry ice to UWHC Core Laboratory (B4/220).
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| Unacceptable Criteria: |
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Hemolyzed specimens, clotted specimens, partially filled tubes and whole blood specimens greater than 4 hours old when received by the laboratory are not acceptable.
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| Stability: |
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Ambient: 4 hours
Refrigerated: Not acceptable
Frozen: 2 weeks at -20°C; 6 months at -70°C
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Interpretation
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Reference Interval:
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| 0 days - 4 days: |
28.0-50.0 seconds |
| 5 days - 29 days: |
22.0-50.0 seconds |
| 30 days - 6 months: |
24.0-38.0 seconds |
| 7 months and up: |
26.0-35.0 seconds |
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| Critical Calls: |
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View
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| Additional Information: |
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See UWHC Pharmacy therapeutic heparin dosing guidelines.
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PTT APTT Activated Partial Thromboplastin Time
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