Activated Partial Thromboplastin Time (APTT)

Method Name

Photo-Optical Clot Detection


Activated Partial Thromboplastin Time; APTT; PTT, APTT

Specimen Required

One full 2.7 mL (3.2% sodium citrate) blue top tube. Specimen will be rejected if the tube is underfilled or overfilled.

Specimen Minimum Volume

2.7 mL of blood

Specimen Stability Information

Specimen is stable for 8 hours at room temperature or 4 hours if the patient is receiving unfractionated heparin. Stability can be extended to 2 weeks if platelet poor plasma is frozen and stored at -20C.

Performing Laboratory

As ordered. Turn around time is 2 hours.

Reference Values

23.4 – 37.3 seconds