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Test Name:
Lupus Anticoagulant Detection


  • SBMF No:
    25243
  • Performance Lab Name:
    Coagulation
  • Test Mnemonic:
    LA
  • ABN:
    For APTT: See Medical Necessity Guide
    National Coverage Determination (NCD) for Partial ThromboplastinTime (PTT) (190.16)
    For PT: See Medical Necessity Guide
    National Coverage Determination (NCD) for Prothrombin Time (PT) (190.17)
  • CPT Code:
    85610; 85613; 85705; 85730
  • Test Includes:
    Dilute Russell Viper Venom Time (dRVVT)
    Partial Thromboplastin Time, Activated (APTT)
    Prothrombin Time (PT)
    Tissue Thromboplastin Inhibition (TTI)
         • NOTE: TTI is also known as Dilute Prothrombin Time (dPT)
  • Also Known As:
    Anticoagulant, Circulating; Circulating Anticoagulant; CAS; Lupus-Like Anticoagulant; LA
  • Spec Type:
    Platelet-poor plasma (PPP)
  • Spec Container:
    Light blue top (3.2% buffered sodium citrate) tube
  • Pref Vol:
    2.0 mL (Two aliquots, 1.0 mL each)
  • Min Vol:
    1.0 mL
  • Fasting:
    No
  • Patient Prep:
    Collect prior to initiation of anticoagulant therapy
  • Spec Collect:
    Routine venipuncture
    NOTE: Traumatic puncture invalidates sample for coagulation studies and necessitates recollection
    • Observe proper collection order for coagulation tests; collect tubes for coagulation studies prior to collecting tubes containing clot activators, additives, or anticoagulants
    • Fill light blue top tube to stated tube volume
    • If coagulation study is only test ordered, collect 1.0 to 2.0 mL blood into tube for discard, then collect light blue top coagulation study tube(s)
    • If multiple coagulation studies are requested, submit additional samples for each coagulation test
    • Immediately after collection, gently invert tube to mix
  • Spec Process:
    Separate plasma from cells immediately
    • Promptly centrifuge 15 minutes
    • Carefully transfer plasma portion of sample to separate plastic tube using plastic pipette
    NOTE: Buffy coat layer of sample must be avoided
    • Centrifuge transferred plasma sample again to produce platelet-poor plasma (PPP)
    • Use second plastic pipette to carefully transfer PPP sample into plastic aliquot tubes
    • Immediately freeze PPP samples
  • Spec Store Transport:
    Frozen
  • Spec Stability:
    4 hours room temperature (20-30°C)
    2 weeks frozen (-20°C) (Avoid repeated freeze/thaw cycles)
  • Spec Reject:
    Citrate tube underfilled
    Sample clotted or hemolyzed
    Plasma not frozen within 4 hours of collection
  • Spec Remarks:
    Platelet-poor plasma (PPP) samples obtained by double centrifugation are critical for accurate coagulation studies as platelet contamination may cause spurious results
  • Methodology:
    Clot Detection
  • Use:
    Determine the presence of lupus-like anticoagulants (LA)
  • Clinical Significance:
    Lupus-like anticoagulants (LA) are immunoglobulins that interfere with one or more of the in vitro phospholipid-dependent steps of coagulation, resulting in prolonged coagulation tests, especially APTT, dRVVT, and TTI. Circulating lupus-like anticoagulants are recognized as a major cause of both venous and arterial thromboembolic events. Often encountered in settings such as recurrent abortion, deep vein thrombosis, and arterial thrombosis, LA may initially present as a prolonged APTT screen.The antiphospholipid protein antibody family includes lupus-like anticoagulants and cardiolipin antibodies, either of which can cause the syndromes described above. Patients may present with lupus-like anticoagulants and cardiolipin antibodies, or with one or the other. The Lupus Anticoagulant Detection test (#25243) plus Cardiolipin IgG and IgM antibodies (#28102 and #28103) are recommended for patients suspected of having a hypercoagulapathy due to an antiphospholipid protein antibody syndrome.
  • Reference Range:
    Normal: No lupus-like anticoagulants (LA) present
    PT: 11-14 seconds
    APTT: Less than or equal to 34 seconds
    LA1: Less than or equal to 45 seconds
    LA2: Less than or equal to 38 seconds
    TTI Ratio: Less than or equal to 1.3
  • Additional Test Info:

    Online LIS Test Build Information is not available for this test. For a complete test mix, contact interface support at ITDMUS@sbmf.org.

  • Day Run:
    Mon-Fri
  • Time Run:
    7:00 am
  • Time Reported:
    5:00 pm
  • Test Type:
    COAGULATION