Test Code ATIII Antithrombin III, Functional

Synonyms/Keywords

AT III, Antithrombin III Activity

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
*Platelet Poor Plasma	3.2% Citrated Blue Top Tube (BTT)		0.75 mL	0.75 mL	0.5 mL

Collection/Processing Instructions

One 0.75 mL citrated (BTT) plasma aliquot.

If more than one coagulation test is ordered, a separate aliquot is needed for each test.

Collect in Citrated Blue Top Tube (BTT) - Citrate anticoagulant must be adjusted for HCT >55%. - Tube must be at least 90% full.
Invert completely 3-4 times (without shaking) to mix.
*See Instructions for: Preparation of Platelet Poor Plasma

Specimen Stability Information

Specimen Type	Temperature	Time
Platelet Poor Plasma	Room Temperature (15 to 25° C)	4 hours
Platelet Poor Plasma	Frozen	6 months

Rejection Criteria

Specimen tubes under-filled (below the fill line) and over-filled (above the fill line)
Gross Hemolysis
Clotted
Frozen whole blood
Contamination with IV or Hickman Line fluids
Specimens that thaw during storage or transport
Specimens with HCT >55% that have not had the citrate anticoagulant adjusted

Test Information

See Clinical Practice Guidelines (Hypercoagulability) for more information

Reference Range Information

Performing Location	Reference Range
Marshfield	80-120%

Marshfield Labs Performing Department

Marshfield Labs Hematology

Performing Information

Performing Location	Day(s) Test Performed	Analytical Time	Methodology/Instrumentation
Marshfield	Monday through Friday	Less than 2 hours	Chromogenic/Siemens Siemens Sysmex CS 2500)

CPT Codes

CPT	Modifier (if needed)	Quantity	Description	Comments
85300

Outreach CPT Codes

CPT	Modifier (if needed)	Quantity	Description	Comments
85300

Ordering Applications

Ordering Application	Description
COM	Antithrombin III Functional