COVID-19 information for patients and families

To help protect our people, patients and communities, we are screening everyone who enters our main hospital buildings. Some of our entrances may be closed or have reduced access.

Please check our COVID-19 information page for more updates before coming to our sites.


Text size: a a a

Laboratory Medicine

Test catalogue

Partial Thromboplastin Time, Activated (aPTT)

Test name

Partial Thromboplastin Time, Activated (aPTT)

Blue top Specimen Type / Requirements

Container Type = Blue

Minimum Volume = 9:1 Ratio – Full Draw

Specimen Handling

Collection Instructions: Collect blood into blue top vacutainers which contain 3.2% buffered sodium citrate. Must indicate anticoagulant status to avoid delay. NOTE: The ratio of blood to anticoagulant is 9 parts blood to 1 part anticoagulant, therefore the blue top vacutainer (citrate) must be filled AT LEAST ¾ in total volume.

Write your initials, date and time of collection on the collection label.

Stability: Stable frozen at -20C for up to two weeks or -70C for up to six months.

Transportation: Send sample to core lab as soon as possible. Specimens that cannot be tested within the suitable time frame (4hrs after Collection) are to be double-spun and send frozen.

Laboratory Staff Instructions: Centrifuge the blood sample at 4000 RPM (1500 G) for 8 minutes at room temperature (18-24˚C) on the Haematology robotics line centrifuge.

Sample Rejection Criteria:Clotted sample, Grossly hemolyzed samples, Unlabeled or Not Sufficient Quantity Samples will be rejected.

Required Documentation

Regular HIS order or Biochemistry requisition required.

Turnaround Time (TAT)

STAT:45min, Routine:4hrs

Test Utilization

Routine

Reference Value

24.0 - 37.0 seconds

Therapeutic range of heparin: 61.0 – 95.0 seconds

Test Code

RPTT

Methodology

Clot Based Assay

Testing Location

SMH-Routine Coagulation

Other Information

Last Updated: June 06, 2019