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Antithrombin Activity (LABCORP)
Test Code99901000273
Alias/See Also
LAB311: Antithrombin III LAB7322: Hypercoaguable Profile | LABCORP EAP: 015040
CPT Codes
85300x1
Preferred Specimen
LABCORP LAB: LT BLUE TOP-CITRATE (Frozen) Min Vol: 1
Other Acceptable Specimens
LABCORP LAB: NA CITRATE ALIQUOT: (Frozen) Min Vol: 1
Transport Temperature
Specimen: Plasma, frozen
Volume: 1 mL
Container: Blue-top (sodium citrate) tube
Collection: Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Special Instructions: If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions.
Storage Requirements:
Container Storage
Plasma from Light Blue Top TubeFrozen
Storage Instructions: Freeze.
Patient Preparation: Do not draw from an arm with a heparin lock or heparinized catheter. Patients ideally should not be on unfractionated heparin or direct Xa inhibitor anticoagulant therapy.
Volume: 1 mL
Container: Blue-top (sodium citrate) tube
Collection: Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.
Special Instructions: If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions.
Storage Requirements:
Container Storage
Plasma from Light Blue Top TubeFrozen
Storage Instructions: Freeze.
Patient Preparation: Do not draw from an arm with a heparin lock or heparinized catheter. Patients ideally should not be on unfractionated heparin or direct Xa inhibitor anticoagulant therapy.
Specimen Stability
Stability Requirements:
Temperature Period
Room temperature
Refrigerated
Frozen 28 days
Freeze/thaw cycles Stable x3
Temperature Period
Room temperature
Refrigerated
Frozen 28 days
Freeze/thaw cycles Stable x3
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Cause for Rejection:
Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability
Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability
Report Available
LABCORP LAB
STAT: 5760 min
Routine: 5760 min
Extended TAT: No TAT min
Timed: 5760 min
Life or Death: 5760 min
STAT: 5760 min
Routine: 5760 min
Extended TAT: No TAT min
Timed: 5760 min
Life or Death: 5760 min
Last Updated: August 29, 2025
