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Test ID A2PI Alpha-2 Plasmin Inhibitor, Plasma

Specimen Required

Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.

2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

3. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, ≤-40° C.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.

Useful For

Diagnosing congenital alpha-2 plasmin inhibitor deficiencies (rare)


Providing a more complete assessment of disseminated intravascular coagulation, intravascular coagulation and fibrinolysis, or hyperfibrinolysis (primary fibrinolysis), when measured in conjunction with fibrinogen, fibrin D-dimer, fibrin degradation products, soluble fibrin monomer complex, and plasminogen


Evaluating liver disease


Evaluating the effects of fibrinolytic or antifibrinolytic therapy

Method Name


Reporting Name

Alpha-2 Plasmin Inhibitor, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Clinical Information

Alpha-2 plasmin inhibitor (antiplasmin) is synthesized in the liver with a biological half-life of approximately 3 days. It inactivates plasmin, the primary fibrinolytic enzyme responsible for remodeling the fibrin thrombus, and binds fibrin, together with factor XIIIa, making the clot more difficult to lyse. Absence of alpha-2 plasmin inhibitor results in uncontrolled plasmin-mediated breakdown of the fibrin clot and is associated with increased risk of bleeding.

Reference Values

Adults: 80-140%

Normal, full-term, and premature infants may have mildly decreased levels (≥50%) which reach adult levels ≤ 90 days postnatal.*

*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing.


Patients with congenital homozygous deficiency (with levels of <10%) are clinically affected (bleeding). Heterozygotes having levels of 30% to 60% of mean normal activity are usually asymptomatic.


Lower than normal levels may be suggestive of consumption due to activation of plasminogen and its inhibition by alpha-2 plasmin inhibitor.


The clinical significance of high levels of alpha-2 plasmin inhibitor is unknown.

Clinical Reference

1. Lijnen HR, Collen D: Congenital and acquired deficiencies of components of the fibrinolytic system and their relation to bleeding or thrombosis. Blood Coagul Fibrinolysis. 1989;3:67-77

2. Francis RB Jr: Clinical disorders of fibrinolysis: A critical review. Blut. 1989 Jul;59(1):1-14

3. Aoki N: Hemostasis associated with abnormalities of fibrinolysis. Blood Rev. 1989 Mar;3(1):11-17

4. Singh S, Saleem S, Reed GL: Alpha2-antiplasmin: The devil you don’t know in cerebrovascular and cardiovascular disease. Front Cardiovasc Med. 2020 Dec 23;7:608899

Day(s) Performed

Monday through Friday

Report Available

3 to 7 days

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
A2PI Alpha-2 Plasmin Inhibitor, P 27810-1


Result ID Test Result Name Result LOINC Value
A2PI Alpha-2 Plasmin Inhibitor, P 27810-1


If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.