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
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
PSPTG | PS/PT Ab, IgG, S | Yes | Yes |
PSPTM | PS/PT Ab, IgM, S | Yes | Yes |
Second-tier phospholipid
Serum
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.
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.
0.4 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 21 days | |
Frozen | 21 days |
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
There is evidence from multiple studies to suggest that patients with APS may develop autoantibodies to other phospholipid/protein complexes, specifically phosphatidylserine/prothrombin (PS/PT).(4-9) Like beta 2-glycoprotein-dependent I cardiolipin, PS/PT is a complex composed of the anionic phospholipid phosphatidylserine and the protein cofactor prothrombin. In a systematic review, Sciascia et al demonstrated that the presence of anti-PS/PT IgG antibodies is an independent risk factor for arterial and/or venous thrombotic events, with odds ratio (OR) of 5.11 (95% CI: 4.2-6.3).(4) A multicenter study showed that IgG anti-PS/PT were more prevalent in APS patients (51%) than in those without (9%), OR 10.8, 95% CI (4.0-29.3), p <0.0001.(5) Furthermore, a number of studies have shown clinical and laboratory evidence that PS/PT antibodies may be a useful second-line test for the evaluation of patients at-risk or suspected with suspected APS, particularly for those individuals with evidence of thrombosis or abnormal LAC testing.(6,7) While anti-PS/PT antibodies were highly prevalent and correlated with other anti-PL antibodies, IgG anti-PS/PT conferred a high risk for thrombosis (8,9) but not for pure hematologic involvement.(9) These antibodies may also be seen in patients with other autoimmune diseases such as systemic lupus erythematosus.(5,8) In individuals who test positive for antiphospholipid antibodies without clinical features of APS (carriers), the cumulative incidence rate of thrombotic events has also been reported to be significantly higher for anti-PS/PT IgG positive than anti-PS/PT IgM positive subjects.(10)
Negative < or =30.0 U
Borderline 30.1-40.0 U
Positive > or =40.1 U
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 the diagnosis of APS, as other phospholipid/protein antibodies are also associated with this disorder.
Anti-phosphatidylserine/prothrombin complex IgM antibodies have a lower risk for APS-associated thrombotic events compared to the IgG isotype in carriers.
A negative result for anti-phosphatidylserine/prothrombin IgG and IgM antibodies does not exclude the diagnosis of APS.
Anti-phosphatidylserine/prothrombin IgG and IgM antibodies are not yet included in the classification criteria for APS.
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
The QUANTA Lite sPS/PT assay is an enzyme-linked immunosorbent assay. 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. INOVA Diagnostics; Rev. 2, 1/2016; QUANTA Lite aPS/PT, IgM ELISA kit. INOVA Diagnostics; Rev. 4, 09/2018)
Wednesday
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.
86148 x 2
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
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
PSPTM | PS/PT Ab, IgM, S | 85358-0 |
PSPTG | PS/PT Ab, IgG, S | 85359-8 |