Synonym
Tubes
- Blue (sodium citrate) top tube
- 5-7 mL of venous blood
Additional information
- Avoid warfarin for 2 weeks and heparin for 2 days prior to the test
- Blood to be drawn with minimal vascular injury
- Placement of tourniquet for more than one minute to be avoided
- Ensure adequate mixing and handle sample gently to prevent hemolysis
- Send sample to lab immediately, if delayed freeze the sample
Info
- Lupus anticoagulant test is a panel of sequential anticoagulant in-vitro tests to detect lupus anticoagulant (LA) antibodies in blood
- LA is an antiphospholipid antibody that prolongs phospholipid dependent in-vitro coagulation assays such as activated partial thromboplastin time (aPTT). This is done by neutralizing the anionic phospholipid-protein complexes that are involved in the coagulation cascade
- The term 'lupus anticoagulant' is a misnomer as it is also found in persons without lupus and does not have anticoagulant function in-vivo, but its presence may result in hypercoagulability and thrombosis
- LA is usually associated with antiphospholipid syndrome (APS), venous thrombosis, pulmonary embolism, arterial thrombosis, and/or recurrent fetal loss
Clinical
- The clinical utility of lupus anticoagulant test includes:
- Evaluation of prolonged partial thromboplastin time (PTT) on routine pre-surgical screening
- Evaluation of venous or arterial thrombotic episodes and recurrent fetal loss, especially in 2nd and 3rd trimesters of pregnancy
- Aids in the evaluation and diagnosis of antiphospholipid syndrome
- Antiphospholipid syndrome is an autoimmune heterogenous disorder characterized by antiphospholipid antibodies resulting in thrombosis, stroke, recurrent pregnancy loss, and other related conditions
- Classification criteria for the diagnosis of APS: At least 1 of the clinical criteria and 1 of the laboratory criteria listed below must be met to make a definite diagnosis of APS as per the guidelines set by the International Society for Thrombosis and Hemostasis (ISTH)
- Clinical criteria:
- Vascular thrombosis: One or more thromobotic episodes in the artery, vein, or capillary of any tissue or organ
- Pregnancy morbidities:
- One or more unexplained deaths of a morphologically normal fetus of >= 10 weeks of gestation
- One or more premature births of a morphologically normal fetus at <= 34 weeks of gestation due to severe preeclampsia, eclampsia, or placental insufficiency
- Three or more unexplained consecutive spontaneous abortions at < 10 weeks of gestation, with the chromosomal causes and maternal anatomic and hormonal causes being excluded
- Laboratory criteria:
- Medium or high titers of anticardiolipin antibody of IgM or IgG type present in the blood, on two or more occasions at least 6 weeks apart
- Lupus anticoagulant present in the blood on two or more occasions at least 6 weeks apart
- Presence of anti-ß2 glycoprotein 1 antibodies of IgG and/or IgM class in high titer, on two or more occasions at least 6 weeks apart
- Features seen with APS but not included in the classification criteria include:
- Dermatological
- Cutaneous necrosis
- Livedo reticularis
- Painful purpura
- Splinter hemorrhages
- Superficial thrombophlebitis
- Hematological
- Coombs positive hemolytic anemia
- Thrombocytopenia
- Obstetrical
- Decreased amniotic fluid
- Fetal growth retardation
- Intrauterine deaths
- Late abortions
- Pre-eclampsia
- Other conditions
- Avascular necrosis of bone in the absence of other risk factors
- Neurological manifestations
- Chorea
- Dementia (rarely)
- Guillain Barre syndrome
- Migraine headaches
- Seizures
- Transverse myelitis
- Pulmonary hypertension
- Unexplained adrenal insufficiency
- Valvular heart disease
- Vascular
- Arterial thrombosis
- Stroke
- Abnormal results on fundoscopy (retinal artery occlusion)
- Aortic or mitral insufficiency
- Digital ulcers
- Gangrene
- Myocardial infarction
- Venous thrombosis
- Abnormal results on fundoscopy (retinal vein thrombosis)
- Ascites (Budd Chiari syndrome)
- Deep vein thrombosis
- Renal vein thrombosis
- Pulmonary edema
Additional information
- The LA antibodies are heterogeneous and no single assay will detect and identify all cases. Hence a series of assays are performed, which is also known as coagulation mixing studies to arrive at the diagnosis:
- Activated partial thromboplastin time (aPTT) is prolonged
- aPTT fails to get corrected when affected individual's plasma is mixed in 1:1 dilution with normal plasma, as lupus anticoagulant acts as inhibitor
- Prothrombin time (PT) may be normal or slightly prolonged
- Serum fibrinogen level may be normal
- Thrombin time (TT) may be normal
- Reptilase time may be normal
- Dilute Russell viper venom test (dRVVT0) is a sensitive assay and its presence is indicative of LA
- Anticardiolipin detected by separate assays
- Prolongation of clot-based assays is highly dependent on the sensitivity of the reagent employed
- If results are inconclusive, repeat testing
- All positive results are repeated after 6-12 weeks for confirmation
- Factors interfering with the test results include:
- Frozen or clotted specimen
- Hemolyzed sample
- Contaminated sample
- Icteric or lipemic samples (with optical testing methods)
- Non-sodium citrate plasma
- Anti-coagulant therapy such as warfarin within 2 weeks or heparin within 2 days prior to the test
- Persons with deficient factors II, V, and X (prolonged times)
- Vascular injury during blood collection
- Venous stasis due to placement of a tourniquet for longer than one minute
- Contamination of the sample with tissue thromboplastin
- Related laboratory and other tests include:
Nl Result
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
- Normal: No lupus anticoagulant detected
High Result
Conditions associated with the presence of lupus anticoagulant antibodies, include:
- Autoimmune disorders
- Antiphospholipid syndrome
- Idiopathic thrombocytopenic purpura (ITP)
- Rheumatoid arthritis (RA)
- Sjogren syndrome
- Systemic lupus erythematosus (SLE)
- Chronic inflammatory states
- Familial
- Infections
- Bacterial
- Protozoal
- Viral (AIDS)
- Malignancy
- Nephrotic syndrome
- Postpartum
- Ulcerative colitis
- Drugs
- Chlorpromazine
- Heparin including LMWH (such as Enoxaparin)
- Hydralazine
- Phenothiazines
- Phenytoin
- Procainamide
- Quinine
References
- ARUP Consult®. Antiphospholipid Syndrome - APS. [Homepage on the Internet]©2008. Last updated in September 2008. Last accessed on September 29, 2008. Available at URL: http://www.arupconsult.com/Topics/HematologicDz/APS.html
- ARUP Laboratories®. Lupus Anticoagulant Reflexive Panel. [Homepage on the Internet]©2008. Last accessed on September 29, 2008. Available at URL: http://www.aruplab.com/guides/ug/tests/0030181.jsp
- eMedicine from WebMD®. Hypercoagulability: Hereditary Thrombophilia and Lupus Anticoagulants Associated With Venous Thrombosis and Emboli. [Homepage on the Internet] ©1996-2008. Last updated on April 30, 2007. Last accessed on September 29, 2008. Available at URL: http://www.emedicine.com/med/TOPIC3776.HTM
- Favaloro EJ et al. Laboratory testing and identification of antiphospholipid antibodies and the antiphospholipid syndrome: a potpourri of problems, a compilation of possible solutions. Semin Thromb Hemost. 2008 Jun;34(4):389-410.
- Giannakopoulos B et al. How we diagnose the antiphospholipid syndrome. Blood. 2008 Aug 28.
- Laboratory Corporation of America. Lupus Anticoagulant With Reflex. [Homepage on the internet]©2007. Last updated on February 8, 2008. Last accessed on September 29, 2008. Available at URL: http://www.labcorp.com/datasets/labcorp/html/chapter/mono/cf006800.htm
- Ledford-Kraemer MR. Laboratory testing for lupus anticoagulants: pre-examination variables, mixing studies, and diagnostic criteria. Semin Thromb Hemost. 2008 Jun;34(4):380-8.
- Wong RC et al. A consensus approach to the formulation of guidelines for laboratory testing and reporting of antiphospholipid antibody assays. Semin Thromb Hemost. 2008 Jun;34(4):361-72.