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Lab Manual for Moffitt-Long and Mount Zion

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POCT Activated Clotting Time

Item Value
Approval req'd? No
Available Stat? Yes
Test code
Performed by Authorized Point of Care testing site staff
Method Hemochron Elite: Clotting activation & optical clot detection
Collection Instructions Samples should be tested as soon as possible after collection.
Container type Special cartridge specific for the level of heparinization used (See Additional information)
Amount to Collect 200 µL (0.2 mL)
Sample type Whole blood
Preferred volume 50 µL (0.05 mL)
Min. Volume 15 µL (0.015 mL)
Units seconds
Normal range Testing is used to monitor anticoagulation during invasive procedures. ACT levels during anticoagulation are compared to patient baseline values.

Cartridge Normal range
LR cartridge 99-187 sec
Plus (+) cartridge 98-139 sec


See Additional Information for reportable ranges and heparin ranges appropriate for each cartridge.
Synonyms ACT; Activated coagulation time; CT
Additional information ACT testing is performed in the operating rooms, Interventional radiology and Cardiac catheterization areas and on selected patient floors. It is not performed or offered by the UCSF Clinical Laboratories.

The HEMOCHRON Elite ACT test is intended for monitoring patients receiving heparin anticoagulation therapy. Two ranges of therapeutic heparinization may be monitored by using either the low range (LR) or high range (Plus) cartridges respectively:

Cartridge Heparin level Reportable range
LR up to 2.5 U/mL 65-400 sec
Plus(+) 1.0-6.0 U/mL 67-1005 sec


Note: Although the reportable ranges overlap, due to the use of different clotting activators in the LR (celite) and Plus (kaolin) cartridges the ACT values derived from these two cartridges are NOT comparable.

ACT is affected by poor sample collection technique. When the sample is collected by venipuncture, use a two syringe technique to prevent tissue thromboplastin contamination. Care must be taken to adequately flush fluids from indwelling lines or catheters with patient blood before collection. Poor collection technique affects precision and accuracy. The following sample problems may effect results:
1. presence of bubbles or foaming
2. Hemolysis
3. Clotted or partially clotted sample

The following clinical conditions may affect the ACT result: hemodilution, cardioplegic solutions, hypothermia, platelet dysfunction, hypofibrinogenemia and other coagulopathies, and unsuspected heparin or warfarin therapy.

Samples with Hematocrits < 20% or > 55% may have optical densities outside of the operating range of the instrument and may results in 'Sample not seen' error message

Patients with Antiphospholipid Syndrome (APL) may have antibodies that interact with the ACT and cause spurious results. Although not extensively studied with the Hemochron Elite system, patients with this syndrome who require heparin anticoagulation should not be monitored with the ACT and an alternate method should be used.
LDT or Mod FDA? No
Last Updated 5/22/2013 1:56:14 PM
Entry Number 1072
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