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Test Code DILTTA Dilute TT - Argatroban

Specimen Type



Light Blue top tube, 3.2% sodium citrate

Preferred Volume

2.7 mL

Offsite Collection Instructions

See UCMC Collection Information

UCMC Collection Instructions

Test is available 7am until 10pm 7 days/week. Specimens collected between 10pm and 7am will be processed and run the next morning.


Collect 24/7, test run 7 days/week from 7:00 am – 10:00 pm

Turnaround Time

5 Hrs

STAT Availability

Not Available

Test Methodology


Additional Information

All 3.2% sodium citrate tubes require a ratio of 9 parts blood to 1 part anticoagulant  (Example:  a 3.0 mL tube requires 2.7 mL blood added to 0.3 mL anticoagulant)


1. When baseline PTT is normal, argatroban is traditionally monitored using prolongation of PTT

2. When baseline PTT is prolonged (such as in the presence of a lupus anticoagulant), PTT can be unreliable in argatroban monitoring. In this case, an alternative approach is the Dilute Thrombin Time test. When this test is ordered, results are reported as follows: 

a. Dilute Thrombin Time, in seconds 

b. The corresponding estimated plasma concentration of argatroban, obtained from a standard curve 

c. The corresponding PTT and fold-increase in PTT that would be anticipated in patients with baseline normal PTT, also obtained from a standard curve. 

3. When switching from a DTI to Coumadin, a Chromogenic assay for Factor X can be used to monitor the Coumadin/Warfarin effect without interference by the DTI.

CPT Code


Minimum Volume

2.7 mL

Fee Code



Dilute Thrombin Time; Argatroban Monitoring