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Labcorp Oklahoma, Inc.
Test Directory


Index:

PT with INR (Prothrombin Time) and
aPTT (Activated Partial Thromboplastin Time)

Order Name PT/PTT
Test Number: 1500425
Revision Date 12/28/2017
Test Name Methodology LOINC Code
Prothrombin Time
Clot Detection 5902-2 
International Normalized Ratio (INR)
Clot Detection 6301-6 
Activated Partial Thromboplastin Time (aPTT)
Clot Detection 3184-9 
SPECIMEN REQUIREMENTS
Specimen Specimen Volume (min) Specimen Type Specimen Container Transport Environment
Preferred 1.5 mL Double Spun Plasma Sterile, Capped Plastic Tube Frozen
Alternate 1 2.7 mL Whole Blood Sodium Citrate 3.2% (Blue Top) Room Temperature
Instructions Please indicate anticoagulant therapy. 
Each 2.7mL Sodium Citrate 3.2% (Blue Top) tube must be filled to the proper level, no hemolysis. Improperly filled tubes can give erroneous results.
Whole blood must be transported to lab immediately.
If testing cannot be started within 4 hours of collection the specimen must be double spun then 1.5 mL plasma aliquot from each tube into individual plastic aliquot tubes and freeze.
Do not pool aliquots together!
Specimen Stability: Un-Frozen specimens are only good for 4 hours. If the patient is on Heparin, Un-Frozen specimens are only good 2hrs.
GENERAL INFORMATION
Testing Schedule Daily  
Expected TAT 1 Day  
Clinical Use Prothrombin Time (PT) and INR
This test is often used to monitor warfarin (coumadin) effect. It may also be used to screen for hemostatic dysfunction involving the extrinsic system as a result of liver disease, vitamin K deficiency, factor deficiency or DIC. 

Activated Partial Thromboplastin Time (aPTT)
This test is most commonly used to monitor heparin therapy. It is also prolonged with deficiencies of clotting factors of the intrinsic system and the common pathway. Presence of antifactor antibodies, and other inhibitors may also be detected with this test. 
CPT Code(s) 85730, 85610
Lab Section Coagulation