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Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

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Item Value
ClinicalQuestion Does my patient have antiphospholipid syndrome (APLS)?
TestEntryNumber 836
TestCode RVVTM
TestName Activated Partial Thromboplastin Time
Synonyms PTT; aPTT; Monitoring Anticoagulation; Monitoring heparin
IsThisScreeningTest No
PubMedID 18755986, 16420554, 12393574, 22951216
Comment In the context of diagnosing anti-phospholipid syndrome, a test for a lupus anticoagulant should be performed by at least 2 methods (at UCSF, the two tests are the Russel's viper venom and a PTT-based hexogonal phospholipid neutralization) in conjunction with other laboratory tests (all pertinent labs are included in the anti-phopholipid antibody panel) in patients who meet clinical criteria as defined in the revised Sapporo criteria (J Thromb Haemost. 2006;4(2):295). The laboratory evaluation should take place at least 12 weeks after a qualifying clinical event and be repeated at least 12 weeks after the first round of tests. We do not recommend testing for anti-phospholipid syndrome at the time of an acute event. The presence of clinical criteria and at least one positive laboratory criteria (with repeat positivity at least 12 weeks apart) establishes a diagnosis of anti-phospholipid syndrome.

Studies have shown that the presence of a lupus anticoagulant is more predictive of thrombosis than high titers of anti-cardiolipin or anti-beta-2-glycoprotein.

Testing for lupus anticoagulant in the presence of anticoagulant therapy (including warfarin, direct thrombin inhibitors & direct factor 10a inhibitors, and supratherapeutic heparin) is not recommended due to possible interference with test results. The presence of factor deficiencies or a factor specific inhibitor may also interfere with this assay.
Sensitivity NA
Specificity NA
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