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Test Code PSPTG Phosphatidylserine/Prothrombin Antibody, IgG, Serum

Reporting Name

PS/PT Ab, IgG, S

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Detecting IgG antibodies against phosphatidylserine/prothrombin complex in patients with strong suspicion of antiphospholipid syndrome (APS) who are negative for the APS criteria laboratory tests (lupus anticoagulant, IgG and IgM anticardiolipin/beta 2-glycoprotein I and anti-beta 2-glycoprotein I antibodies)

 

May be useful for the evaluation of patients with prior positive lupus anticoagulant results who are on direct oral anticoagulant therapy

 

May be useful as a risk marker for thrombosis in antiphospholipid antibody carriers


Ordering Guidance


Cardiolipin and beta-2 glycoprotein testing are the first-tier test options for most patients. Phosphatidylserine/prothrombin antibodies are considered part of the second-tier workup.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Type

Serum

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK
Heat treated Reject

Reference Values

Negative ≤30.0 U

Borderline 30.1-40.0 U

Positive ≥40.1 U

Interpretation

A positive and persistent result for anti-phosphatidylserine/prothrombin complex IgG antibodies may be suggestive of a diagnosis of antiphospholipid syndrome (APS) in patients with evidence of arterial, venous, or specific pregnancy-related morbidities. These antibodies may also exist prior to the occurrence APS clinical manifestations as well as in patients with other systemic autoimmune diseases such systemic lupus erythematosus.

 

Anti-phosphatidylserine/prothrombin complex IgG antibodies have relatively higher correlations with positive results for lupus anticoagulant than the IgM isotype as well as significant risk for APS-associated thrombotic events compared to the IgM isotype in antiphospholipid antibody carriers.

 

A negative result does not exclude a diagnosis of APS, as other phospholipid and/or protein antibodies are also associated with this disorder.

Day(s) Performed

Wednesday

Report Available

2 to 8 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

86148

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PSPTG PS/PT Ab, IgG, S 85359-8

 

Result ID Test Result Name Result LOINC Value
PSPTG PS/PT Ab, IgG, S 85359-8