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

Reporting Name

PS/PT Ab, IgG/IgM, S

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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


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 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

Clinical Reference

1. Miyakis S, Lockshin MD, Atsumi T, et al: International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost. 2006 Feb;4(2):295-306. doi: 10.1111/j.1538-7836.2006.01753.x

2. Pengo V, Bison E, Denas G, Jose SP, Zoppellaro G, Banzato A: Laboratory diagnostics of antiphospholipid syndrome. Semin Thromb Hemost. 2018 Jul;44(5):439-444. doi: 10.1055/s-0037-1601331

3. Tebo AE: Laboratory evaluation of antiphospholipid syndrome: An update on autoantibody testing. Clin Lab Med. 2019 Dec;39(4):553-565. doi: 10.1016/j.cll.2019.07.004

4. Sciascia S, Sanna G, Murru V, Roccatello D, Khamashta MA, Bertolaccini ML: 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 Feb;111(2):354-364. doi: 10.1160/TH13-06-0509

5. Amengual O, Forastiero R, Sugiura-Ogasawara M, et al: Evaluation of phosphatidylserine-dependent antiprothrombin antibody testing for the diagnosis of antiphospholipid syndrome: results of an international multicentre study. Lupus. 2017 Mar;26(3):266-276. doi: 10.1177/0961203316660203

6. Heikal NM, Jaskowski TD, Malmberg E, Lakos G, Branch DW, Tebo AE: Laboratory evaluation of anti-phospholipid syndrome: A preliminary prospective study of phosphatidylserine/prothrombin antibodies in an at-risk patient cohort. Clin Exp Immunol. 2015 May;180(2):218-226. doi: 10.1111/cei.12573

7. Nakamura H, Oku K, Amengual O, et al: First-line, non-criterial antiphospholipid antibody testing for the diagnosis of antiphospholipid syndrome in clinical practice: A combination of anti-beta 2 -glycoprotein I domain I and anti-phosphatidylserine/prothrombin complex antibodies tests. Arthritis Care Res (Hoboken). 2018 Apr;70(4):627-634

8. Radin M, Foddai SG, Cecchi I, et al: Antiphosphatidylserine/prothrombin antibodies: An update on their association with clinical manifestations of antiphospholipid syndrome. Thromb Haemost. 2020 Apr;120(4):592-598. doi: 10.1055/s-0040-1705115

9. Nunez-Alvarez CA, Hernandez-Molina G, Bermudez-Bermejo P, et al: Prevalence and associations of anti-phosphatidylserine/prothrombin antibodies with clinical phenotypes in patients with primary antiphospholipid syndrome: aPS/PT antibodies in primary antiphospholipid syndrome. Thromb Res. 2019 Feb;174:141-147. doi: 10.1016/j.thromres.2018.12.023

10. Tonello M, Mattia E, Favaro M, et al: IgG phosphatidylserine/prothrombin antibodies as a risk factor of thrombosis in antiphospholipid antibody carriers. Thromb Res. 2019 May;177:157-160. doi: 10.1016/j.thromres.2019.03.006

Report Available

2 to 8 days

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