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Test Code APTTP Activated Partial Thromboplastin Time, Plasma

Reporting Name

Activated Partial Thrombopl Time, P

Performing 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)

Specimen Type

Plasma Na Cit


Advisory Information


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 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) and Time(s) Performed

Monday through Sunday; Continuously

Test Classification

This test has been cleared or approved by the U.S. 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 75506-6

 

Result ID Test Result Name Result LOINC Value
APTTP Activated Partial Thrombopl Time, P 75506-6