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Test Directory - Activated Clotting Time (POCT)

POCT Equipment

Hemochron Signature Elite

Clinical Indications

This test is intended for use in monitoring moderate to high heparin doses frequently associated with cardiac catheterisation and cardio/pulmonary bypass surgery.

Sample Type

Venous whole blood, from extracorporeal blood line port.

Sample Container

Plastic syringe

Sample Volume

0.5 mL

Sample Handling

The sample must be analysed immediately.

Special Precautions

Ensure the sample is not from a line through which heparin or any other IV fluid has been administered.

If collecting blood via venepuncture, use a 23 gauge or larger needle and expel the sample slowly to prevent haemolysis.

Turnaround Time

A result is produced in up to 1000 seconds.

Reference Range

Expected values will depend on the type of surgery being performed.


The test is not sensitive to very low doses of heparin such as those encountered in critical care.

Samples with a hematocrit less than 20% or greater than 55% are not recommended for testing.

Invalid results may be obtained if there is sample contamination with tissue thromboplastin, foaming of the sample (air bubbles), haemolysis, alcohol cleansing solution, visible clotting or debris accumulation.

Time Limit for Additional Tests

Samples can only be used once.

If the test result is inconsistent with patient therapy, re-test with a fresh sample.


The test should only be carried out by a trained member of staff.

Hospital Procedure (SOP)

Standard Operating Procedure for the Measurement of Activated Clotting Time (ACT) on the Hemochron Signature Elite

Last edited 16/04/14