Home
HelpTest Code LAB1856 Phosphatidylserine/Prothrombin Antibody, IgG, Serum
Additional Codes
PSPTG
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
Method Name
Specimen Type
SerumOrdering 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 Minimum Volume
0.4 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318
Submit serum in plastic vial, Refrigerated
Off-campus collections:
Centrifuge and aliquot within 2 hours.
Specimen to be stored/transported Refrigerated
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
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.
Method Description
The QUANTA Lite aPS/PT IgG 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 to the PS/PT complex will bind during an incubation step. After a wash step, an antihuman IgG 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 PSPT antibodies in the sample. Control and patient results are calculated based on a curve generated from the kit calibrators.(Packet insert: QUANTA Lite aPS/PT IgG. INOVA Diagnostics; Rev 2, 01/2016)
Day(s) Performed
Wednesday
Report Available
2 to 8 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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 |