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Activated Partial Thromboplastin Time (aPTT)


This test is performed on a Sysmex fully automated coagulation system which utilizes optical detection technology.

Test Utility

The test is used to measure and evaluate how long it takes to form a clot in blood.

Specimen Collection and Preparation

Collect a blood sample in the following tube:

  • Light Blue 3.2% Sodium Citrate Tube – Tube must be filled to 90% of minimum/maximum etched fill line

  • If possible, centrifuge the specimen at 3000 rpm for 15 min, remove plasma and freeze.

Specimen Storage and Stability

Store whole blood at the following temperatures:

  • Room temperature: 24 hours

  • Refrigerated 2°C to 8°C:  Unacceptable

  • Frozen: Separated plasma only.

Specimen Rejection

  • Insufficient sample volume – Tube must be filled to with 90% of etched fill line

  • Sample not stored at proper temperature

  • Frozen whole blood

  • Hemolyzed samples

  • Severely lipemic specimens

  • Specimen labeled incorrectly or not labeled

Reference Pages


Monday – Saturday

Result available within 24 hours of receipt in laboratory

NOTE: Specimens are refrigerated (2-8°) for 7 days before disposal

STAT results available within 2 hours of receipt in the laboratory


Vibra Health Laboratory  

1307- A, Allen Dr 

Troy, MI 48083 

(248) 846-0663

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