TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: AATHR    
Thrombophilia Profile, Plasma and Whole Blood

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluating patients with thrombosis or hypercoagulability states

 

Detecting a lupus-like anticoagulant; dysfibrinogenemia; disseminated intravascular coagulation/intravascular coagulation and fibrinolysis

 

Detecting a deficiency of antithrombin, protein C, or protein S

 

Detecting activated protein C resistance (and the factor V Leiden [p.Arg534Gln, historically known as R506Q] variant if indicated)

 

Detecting the prothrombin F2 c.*97G>A variant (historically known as G20210A)

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Initial testing includes: prothrombin time (PT); activated partial thromboplastin time (aPTT); dilute Russell viper venom time (dRVVT); thrombin time (bovine); fibrinogen; D-dimer; antithrombin activity; protein C activity; protein S antigen, free;  prothrombin G20210A variant; activated protein resistance V; and thrombophilia interpretation.

 

If the PT is >13.9 seconds, then the PT mixing study will be performed at an additional charge.

 

If the aPTT is > or =38 seconds, then the aPTT mixing study will be performed at an additional charge.

 

If the aPTT mix result is > or =38 seconds and thrombin time is <35.0 seconds (no evidence of heparin), then the platelet neutralization procedure will be performed at an additional charge.

 

If the dRVVT ratio is > or =1.20, then the dRVVT mixing study and dRVVT confirmation will be performed at an additional charge.

 

If the thrombin time is > or =25.0 seconds, then the reptilase time will be performed at an additional charge.

 

If the fibrinogen result is <150 mg/dL or clinically indicated, then PT-fibrinogen will be performed at an additional charge.

 

If the D-dimer result is >500 ng/mL fibrinogen equivalent units (FEU), then soluble fibrin monomer testing will be performed at an additional charge.

 

If the free protein S antigen result is <65% for males and females > or =50 years of age and <50% for females <50 years of age, then the total protein S antigen test will be performed at an additional charge.

 

If the protein C activity is <70% with no evidence for an acquired decrease in protein C activity, then protein C antigen testing may be performed at an additional charge.

 

If the antithrombin activity is <80% with no evidence of an acquired decrease in antithrombin activity, then antithrombin antigen testing will be performed at an additional charge.

 

If the activated protein C resistance (APC) ratio is <2.3 or the baseline APC aPTT is prolonged, then factor V Leiden (R506Q) variant analysis will be performed at an additional charge.

 

If appropriate, protein S activity, coagulation factor assays, or Staclot LA will be performed at an additional charge to clarify significant abnormalities in the screen test results.

 

See Thrombophilia Profile in Special Instructions.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Thrombophilia is defined as an acquired or familial disorder associated with thrombosis. The clinical presentation of an underlying thrombophilia predominantly includes venous thromboembolism (deep vein thrombosis, pulmonary embolism, superficial vein thrombosis). Other manifestations that have been linked to thrombophilia include recurrent miscarriage and complications of pregnancy (eg, severe preeclampsia, abruptio placentae, intrauterine growth restriction, stillbirth). The current thrombophilia does not predict for arterial thrombosis. Demographic or environmental exposures that compound the risk of venous thromboembolism among persons with a thrombophilia include increasing age, male gender, obesity, surgery, trauma, hospitalization for medical illness, malignant neoplasm, prolonged immobility during travel (eg, prolonged airplane travel), oral contraceptive use, estrogen therapy (both oral and transdermal), tamoxifen and raloxifene therapy, and infertility drugs. Central venous catheters and transvenous pacemaker wires increase the risk for upper extremity deep vein thrombosis; this risk is unrelated to thrombophilia.

 

Inherited thrombophilias include:

-Deficiency due to reduced plasma protein level or dysfunctional protein of:

-Antithrombin

-Protein C

-Protein S

-Dysfibrinogenemias (rare)

-Activated protein C resistance due to the factor V Leiden variant (F5 c.1601G>A; p.Arg534Gln, historically known as R506Q)

-Prothrombin F2 c.*97G>A variant (historically known as G20210A)

 

Acquired thrombophilias include a lupus-like anticoagulant (antiphospholipid antibodies) and disseminated intravascular coagulation/intravascular coagulation and fibrinolysis (DIC/ICF). DIC/ICF may cause thrombotic as well as hemorrhagic events. Positive tests for DIC/ICF can also occur as consequences of thrombosis.

 

Acquired deficiencies of fibrinogen, protein C, protein S, and antithrombin may be found in conjunction with liver disease (they are produced by the liver) or DIC/ICF and are of uncertain significance with respect to thrombosis risk.

 

Acquired deficiencies of protein C and protein S are also found in patients with liver disease who are being treated with oral anticoagulants (eg, warfarin, Coumadin), since both of these proteins are dependent upon the action of vitamin K for normal function.

 

Acquired protein S deficiency also occurs in thrombotic thrombocytopenic purpura, pregnancy or estrogen therapy, nephrotic syndrome, and sickle cell anemia. In acute illness, the level of acute-phase reactants rise (including C4b binding protein, which binds and inactivates protein S in the plasma) and the portion of bound protein S also rises leaving a lower proportion of free protein S. The significance of acquired protein S deficiency with respect to thrombosis risk is unknown.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

An interpretive report will be provided.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

To obtain the most useful information, this testing is best performed in medically-stable patients who are not receiving oral vitamin K inhibitor (eg, warfarin, Coumadin), heparin, low-molecular-weight heparin, hirudin (Refludan), argatroban, fibrinolytic agents (eg, streptokinase, tissue plasminogen activator), or platelet GPIIbIIIa (alpha IIb beta3) inhibitors (abxicimab [ReoPro], tirofiban, aggrastat). However, useful information can be obtained in patients receiving anticoagulation therapy.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Pengo V, Tripodi A, Reber G, et al: Update of the guidelines for lupus anticoagulant detection. Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. J Thromb Haemost. 2009;7(10):1737-1740. doi: 10.1111/j.1538-7836.2009.03555.x

2. Keeling D, Mackie I, Moore GW, Greer IA, Greaves M, British Committee for Standards in Haematology: Guidelines on the investigation and management of antiphospholipid syndrome. Br J Haemotol. 2012;157(1):47-58. doi: 10.1111/j.1365-2141.2012.09037.x

3. Clinical and Laboratory Standards Institute (CLSI). Laboratory Testing for the Lupus Anticoagulant; Approved Guideline. CLSI document H60-A. Clinical Laboratory Standards Institute; 2014

Special Instructions Library of PDFs including pertinent information and forms related to the test