Test Directory

This test is used for confirmation and characterization of congenital AT deficiency.

Specimen Type: Citrated Platelet-Poor Plasma

Collection Container: Light Blue Top (Sodium Citrate)

Desired Specimen Volume: 2 mL

1. Collect 2 light blue (sodium citrate) tubes via venipuncture.
2. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.
3. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood.
4. 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.
5. When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes.
6. 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.

 Platelet-Poor Plasma Processing Instructions

1. Perform platelet poor plasma processing procedure.
2. Transfer 2 mL of platelet-poor plasma to a LabCorp PP transpak frozen purple tube.

Do not draw from an arm with a heparin lock or heparinized catheter.

Transport to the laboratory frozen. 

• Severe hemolysis
• Improper labeling
• Clotted specimen
• Specimen diluted with IV fluids
• Samples thawed in transit
• Improper sample type
• Sample out of stability

See patient report.

If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.

AT testing should not be performed on patients on heparin therapy because heparin decreases plasma AT levels. AT results for individuals on warfarin therapy should be interpreted with caution because warfarin can increase levels of AT of patients with heterozygous deficiency into the normal range.