Dilute Thrombin Clotting Time (DTCT)

Testing Laboratories

Department

Haematology

Delphic Registration Code (Alpha Code)

DTCT, NCOA

Test Code (Numeric Code)

1698

Laboratory Handling

Phlebotomy

Tube must be filled up to the "Fill Line"

Sample Stability

24 hours

Associated Tests

• Coagulation Factors

Synonyms

Thrombin Time
TCT
Dilute thrombine clotting time

Turnaround Time

4 hours

Specimen Type

• Plasma

Specimen Requirements

Tube/Container Type:

Preferred

• Citrate (Light Blue Cap)

Preferred Sample Volume (ml)

2.7

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• Citrate (Light Blue Cap)

Preferred Sample Volume (ml)

1

The Dilute Thrombin Clotting Time (DTCT) reflects inhibitors to thrombin e.g. heparin, FDP and fibrinogen abnormalities (low levels, dysfibrinogenaemia) and direct thrombin inhibitors e.g. Dabigatran and Bivalirudin. Prolonged DTCT is common in liver disease and newborn infants (dysfibrinogenaemia). Clinically, these are rarely associated with bleeding problems.
The DTCT is markedly prolonged in the presence of therapeutic levels of direct thrombin inhibitors.

Repeating the DTCT with the addition of protamine sulphate is a useful test to distinguish between the presence of unfractionated heparin and direct thrombin inhibitors. Protamine sulphate will usually inhibit all unfractionated heparin activity returning the DTCT to normal, on rare occasions however gross heparin contamination of the sample may cause the DTCT to not fully correct. Protamine sulphate does not inhibit direct thrombin inhibitors therefore the DTCT and DTCT + protamine results will be very similar.

If the DTCT and DTCT + protamine are both substantially prolonged and the patient is definitely not taking on direct thrombin inhibitor then high paraprotein levels should be considered.

Contact Information