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HelpTest Code APTTP Activated Partial Thromboplastin Time, Plasma
Reporting Name
Activated Partial Thrombopl Time, PPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Monitoring heparin therapy (unfractionated heparin)
Screening for certain coagulation factor deficiencies
Detection of coagulation inhibitors such as lupus anticoagulant, specific factor inhibitors, and nonspecific inhibitors
Method Name
Coagulometric (Turbidimetric)
Ordering Guidance
The primary method for therapeutic heparin monitoring is the heparin anti-Xa assay. Order HEPTP / Heparin Anti-Xa Assay, Plasma.
Specimen Required
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Centrifuge, remove plasma and centrifuge plasma again.
2. Aliquot plasma into plastic vial leaving 0.25 mL in the bottom of centrifuged vial.
Additional Information: Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
Specimen Type
Plasma Na CitSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen (preferred) | 30 days | |
| Ambient | 4 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
25-37 seconds
Interpretation
Prolongation of the activated partial thromboplastin time (APTT) can occur as a result of deficiency of one or more coagulation factors (acquired or congenital in origin), or the presence of an inhibitor of coagulation such as heparin, a lupus anticoagulant, a nonspecific inhibitor such as a monoclonal immunoglobulin, or a specific coagulation factor inhibitor. Prolonged clotting times may also be observed in cases of fibrinogen deficiency, liver disease, and vitamin K deficiency.
Shortening of the APTT usually reflects either elevation of factor VIII activity in vivo that most often occurs in association with acute or chronic illness or inflammation, or spurious results associated with either difficult venipuncture and specimen collection or suboptimal specimen processing.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 dayTest Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
85730
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| APTTP | Activated Partial Thrombopl Time, P | 14979-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| APTTP | Activated Partial Thrombopl Time, P | 14979-9 |