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Test Code ATT3 Antithrombin III Activity

Specimen Type

Blood

Preferred Collection Container

BLUE

Collection Volume

2.7 mL in 2.7 mL tube

Minimum Collection Volume

2.7 mL in 2.7 mL tube

Collection Instructions

Collect specimen in blue top (citrate) tubes. If the specimen is drawn into a plastic Vacutainer tube, then the tube should be gently inverted no more than three or four times; excessive mixing will activate platelets and affect the test result. Specimen should arrive at lab within 4 hours of collection; transport at room temperature. If unable to test samples within 4 hours, perform transfer instructions.

Rejection Criteria

Specimens that are clotted, hemolyzed, diluted with IV fluid, received unfrozen more than 4 hours after collection, insufficient volume, improperly labelled, not double spun (not platelet poor).

Specimen Storage and Stability

Freeze double spun aliquots within 4 hours after collection. Samples may be frozen at -20° C for up to 2 weeks or at -70° C for up to six months.

Turn Around Time

Within 1 week.

Lab Department

Hematology

Alias

Antithrombin III Assay, Functional; Serine Protease Inhibitor;

Ordering Info

NOTE: Collection of blood for coagulation testing through indwelling catheters that have been flushed with heparin should be avoided, if possible. If specimen is drawn through an indwelling catheter, the line should be flushed with 5 ml saline and the first 5 ml of blood or six times the deadspace volume of the catheter being used should be discarded. Proper collection and handling of specimens is critical.

EPIC Code

LAB311

Acceptable Collection Container

BLUE (3.2% buffered sodium citrate)

Transfer Instructions

Centrifuge samples at 1500 g for 15 minutes. Remove plasma with plastic transfer pipette and place into a plastic tube. Centrifuge the transferred plasma at 1500 g for 15 minutes. Transfer plasma to new plastic tubes (1 mL aliquots per tube) and freeze. Store at -20° C for up to 2 weeks or at -70 degrees for up to six months. Transport frozen specimen on dry ice.

Patient Preparation

Not indicated for patients on heparin or low-molecular-weight heparin therapy.

Day(s) and Time(s) Performed

Monday through Friday, 7am to 3pm

STAT Availability

Yes-must call Hematology to make arrangements