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

Reporting Name

PS/PT Ab, IgG/IgM, S

Useful For

Second-tier evaluation of patients with suspected antiphospholipid syndrome


Evaluation of patients with a strong suspicion of antiphospholipid syndrome for whom anticardiolipin/beta 2-glycoprotein I and anti-beta 2-glycoprotein I antibody testing was negative


Evaluation of patients with evidence of a functional lupus anticoagulant


Detection of both IgM and IgG antibodies against phosphatidylserine/prothrombin

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Advisory Information

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


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Collection Information: Centrifuge and aliquot serum.

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) and Time(s) Performed

Tuesday; Evening

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 U.S. Food and Drug Administration.

CPT Code Information

86148 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PSPT PS/PT Ab, IgG/IgM, S In Process


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

Clinical Reference

1. Otomo K, Atsumi T, Amenqual O, et al: Efficacy of the antiphospholipid score for the diagnosis of antiphospholipid syndrome and its predictive value for thrombotic events. Arthritis Rheum 2012;64:504-512

2. Hoxha A, Ruffatti A, Tonello M, et al: Antiphosphatidylserine/prothrombin antibodies in primary antiphospholipid syndrome. Lupus 2012;21:787-789

3. Sciascia S, Sanna G, Murru V, et al: Validation of a commercially available kit to detect anti-phosphatidylserine/prothrombin antibodies in a cohort of systemic lupus erythematosus patients. Thromb Res 2014;133:451-454

4. Sciascia S, Sanna G, Murru V, et al: Anti-prothrombin (aPT) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies and the risk of thrombosis in the antiphospholipid syndrome: A systematic review. Thromb Haemost 2014;111:354-364

5. Heikal NM, Jaskowski TD, Malmberg E, et al: Laboratory evaluation of anti-phospholipid syndrome: A preliminary prospective study of phosphatidylserine/prothrombin antibodies in an at-risk patient cohort. Clin Exp Immunol 2015;180:218-226

Method Description

The QUANTA Lite sPS/PT assay is an enzyme-linked immunosorbent assay (ELISA). Briefly, purified phosphatidylserine/prothrombin (PS/PT) complex is coated onto a 96-well plate. Calibrators, controls, and diluted patient samples are added to the wells of the plate. If present, IgG antibodies or IgM antibodies to the PSPT complex will bind during an incubation step. After a wash step, an antihuman IgG or IgM horseradish peroxidase-labelled conjugate is added. After another incubation and wash step, a peroxidase substrate solution is added, which will change color in the presence of the conjugated enzyme. Lastly, the reaction is stopped by the addition of 0.44 M sulfuric acid. The absorbance of the colored produced is proportional to the amount of IgG or IgM PS/PT antibodies in the sample. Control and patient results are calculated based on a curve generated from the kit calibrators.(Packet inserts: QUANTA Lite aPS/PT, IgG ELISA kit, Rev. 2 1/2016, INOVA diagnostics, San Diego, CA; QUANTA Lite aPS/PT, IgM ELISA kit, Rev. 4 9/2018, INOVA diagnostics, San Diego, CA)

Analytic Time

1 day

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK

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

Secondary ID