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Lupus Anticoagulant Evaluation with Reflex
Test CodeCPT Codes
85613, 85730
Includes
If PTT-LA Screen is prolonged (>40 seconds), then Hexagonal Phase Confirmation will be performed at an additional charge (CPT code(s): 85598).
If Hexagonal Phase Confirmation is positive or weakly positive, then Thrombin Clotting Time will be performed at an additional charge (CPT code(s): 85670).
If dRVVT Screen is prolonged (>45 seconds), then dRVVT Confirm will be performed at an additional charge (CPT code(s): 85597).
If dRVVT Confirm is positive, then dRVVT 1:1 Mixing Study will be performed at an additional charge (CPT code(s): 85613).
Preferred Specimen
1.5 mL (x2) frozen platelet-poor plasma
Minimum Volume
1 mL (x2)
Instructions
Transport Container
Plastic screw-cap vial
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable Refrigerated: Unacceptable Frozen: 90 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Specimens received room temperature or refrigerated • Hemolysis
Methodology
Clot Detection
Setup Schedule
Set up: Mon-Fri (night shift).; Report available: Next day
Limitations
Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: no effect (panel includes mixing studies which correct for Warfarin-induced factor deficiencies); Heparin (UFH or LMWH): possible to misclassify as LA; Dabigatran or Argatroban (Thrombin Inhibitors): panel includes Thrombin Time (TT) which detects thrombin inhibitors, unable to detect if TT significantly abnormal; Rivaroxaban or Apixaban (Factor Xa Inhibitors): possible to misclassify as LA.
Reference Range
Lupus Anticoagulant | Not detected |
PTT-LA Screen | ≤40 sec |
dRVVT Screen | ≤45 sec |
Clinical Significance
Lupus anticoagulants (LA) are members of a family of antibodies with phospholipid-protein specificity. LA may be defined as an immunoglobulin, IgG or IgM or a mixture of both, that interferes with one or more of the in-vitro phospholipid (PL) dependent tests of coagulation. These antibodies are not associated with a hemorrhagic diathesis, but rather have been linked to thrombotic events. In addition to thrombosis other clinical complications have been associated with the presence of LA. These include strokes, nonbacterial thrombotic endocarditis, livedo reticularis and a variety of obstetrical complications such as intrauterine fetal death, recurrent spontaneous abortion, fetal growth retardation, early onset preeclampsia and chorea gravidarum.
Note: Target specific anticoagulant therapy (anti-Xa medications, direct thrombin inhibitors) may cause false positive results.
Performing Laboratory
Quest Diagnostics Nichols Institute 14225 Newbrook Drive Chantilly, VA 20153
Last Updated: February 23, 2012