Activated Partial Thromboplastin Time (APTT), Plasma
Use
The activated partial thromboplastin time (APTT) is used to measure the integrity of the intrinsic and common coagulation pathways, serving as a screening tool for certain coagulation factor deficiencies and abnormalities, such as factors VIII, IX, XI, and XII. It helps detect coagulation inhibitors including lupus anticoagulant and antiphospholipid antibodies. The APTT is also utilized for monitoring unfractionated heparin therapy. It is essential for evaluating a prolonged APTT result to differentiate between coagulation factor deficiencies and inhibitors, especially when used in conjunction with other coagulation tests and clinical data.
Special Instructions
Not provided.
Limitations
The APTT test does not detect all coagulation inhibitors or lupus anticoagulants and may miss mild coagulation factor deficiencies. Sensitivity to factor deficiencies varies with different reagents. Lipemic specimens can interfere with clot detection. A normal or shortened APTT does not exclude a hemostatic defect, necessitating specific clotting factor assays if bleeding diathesis is clinically suspected. APTT mixing studies are ineffective when APTT is normal.
New York Approved
Methodology
Automated Analyzer
Biomarkers
LOINC Codes
- 14979-9 - aPTT PPP
- 14979-9 - aPTT PPP
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
Not provided
Minimum Volume
Not provided
Collection Instructions
Only orderable as part of a special coagulation profile or reflex. Note heparin or Coumadin therapy. Avoid gross hemolysis, lipemia, and icterus.
Causes for Rejection
Gross hemolysis, gross lipemia, gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |