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Test Code PTT Activated Partial Thromboplastin Time (APTT), Plasma

Performing Laboratory

Northwell Health Laboratories


Clotting-ACL® TOP/IL

Reference Values

27.5-37.4 seconds


Recommended therapeutic heparin range (full dose) for APTT is 55-99 seconds.

Recommended therapeutic argatroban range is 1.5 to 3.0 times the baseline APTT value, not to exceed 100 seconds.

Recommended therapeutic refludan range is 1.5 to 2.5 times the baseline APTT.                      

Test Classification and CPT Coding


Physician Office Specimen Requirements

Container/Tube:  Light blue-top (3.2% sodium citrate) tube

Specimen:  Full tube

Transport Temperature:  Refrigerate

Collection Instructions:  1. If no other tube is drawn, draw a discard tube.

2. Fill tube completely.

3. Mix by gently inverting several times.


Day(s) and Time(s) Performed

Monday through Sunday

Computer Interface Code

PDM #  5500540