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HelpTest Code PTT Activated Partial Thromboplastin Time (APTT, PTT), Plasma
Methodology
Mechanical Clot Detection
Specimen Requirements
1. Draw blood in a blue-top (citrate) tube(s). Spin down,
remove plasma, spin plasma again, and place 0.5 mL of citrate
platelet-poor plasma in plastic vial. (Glass vial is
not acceptable.)
Note: Double-centrifuged specimen is
critical for accurate results as platelet contamination may cause
spurious results.
2. Freeze specimen immediately at ≤-40° C, if
possible.
3. Send specimen frozen.
Note: Each coagulation assay requested
should have its own vial.
Specimen Stability Information
| Specimen Type | Temperature | Time |
| Citrate plasma | Room Temperature, Spun | 4 hrs |
| Room Temperature, Spun for PTTH | 2 hrs |
Reference Values
27-39 seconds
Critical values
Anticoagulated: >200 seconds
Non-anticoagulated: >60 seconds
Reject Due To
| Hemolysis | Mild: OK unless patient on Heparin | Gross: Reject |
| Lipemia | Mild: OK | Gross: OK |
| Icterus | Mild: OK | Gross: OK |
Day(s) Test Set Up
Monday through Sunday
CPT Coding
85730
Performing Laboratory
Huntsville Hospital Laboratory/Madison Hospital Laboratory
LOINC Coding
| Test Name | LOINC Code |
|---|---|
|
Activated Partial Thromboplastin Time (APTT, PTT), Plasma |
3173-2 |