Dilute Prothrombin Time
Also known as: Tissue Thromboplastin Inhibition
Use
Qualitative detection of lupus anticoagulants (LA) in plasma6
Special Instructions
It is recommended to test any sample suspected of having LA using two or more LA screening tests, as no single LA test can detect all LA-positive patients. The dPT assay is designed to screen for phospholipid-dependent inhibitors of the extrinsic pathway.
Limitations
Improper preparation of the platelet-poor plasma at collection can reduce the sensitivity of this assay for LA. The dPT assay may be prolonged in patients with congenital or acquired factor deficiencies and those on warfarin therapy. The reagent used can neutralize unfractionated heparin at plasma levels up to 1.0 unit/mL; higher levels may yield anomalous results.
Methodology
Automated Analyzer (Coagulation)
Biomarkers
LOINC Codes
- 75508-2
- 75508-2
- 75884-7
Result Turnaround Time
2-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
Not provided
Container
Blue-top (sodium citrate) tube
Collection Instructions
Citrated plasma samples should be collected by double centrifugation. Blood collected in a blue-top tube containing 3.2% buffered sodium citrate should be mixed immediately by gentle inversion at least six times and double centrifuged prior to freezing.
Patient Preparation
Ideally, patients should not be on anticoagulant therapy. Avoid warfarin (Coumadin®) therapy for two weeks prior to the test and heparin, direct Xa, and thrombin inhibitor therapies for about three days prior to testing. Do not draw from an arm with a heparin lock or heparinized catheter.
Storage Instructions
Freeze.
Causes for Rejection
Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 28 days |
Other tests from different labs that may be relevant