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Test ID PSPT Phosphatidylserine/Prothrombin Antibody, IgG and IgM, Serum

Useful For

Preferred second-tier panel for the detection of IgG and IgM 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

Profile Information

Test ID Reporting Name Available Separately Always Performed
PSPTG PS/PT Ab, IgG, S Yes Yes
PSPTM PS/PT Ab, IgM, S Yes Yes

Reporting Name

PS/PT Ab, IgG/IgM, S

Specimen Type


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

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 Minimum Volume

0.4 mL

Specimen Stability Information

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

Reference Values

Negative ≤30.0 U

Borderline 30.1-40.0 U

Positive ≥40.1 U

Day(s) Performed


Report Available

2 to 8 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86148 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PSPT PS/PT Ab, IgG/IgM, S 97026-9


Result ID Test Result Name Result LOINC Value
PSPTM PS/PT Ab, IgM, S 85358-0
PSPTG PS/PT Ab, IgG, S 85359-8

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.