Medicare Medical Necessity Restrictions May Apply
Medical Necessity Documentation:
Client Notes:
Patient Preparation:
Specimen Requirements:
3.0 mL platelet-poor plasma specimens in plastic vials from Blue Top Tube(s) - 3.2% Na Citrate
Collection Instructions:
Please submit a separate, frozen vial for each coagulation assay ordered. 1st plasma for PTT-LA, 2nd plasma for dRVVT.
Platelet-poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.
Minimum Volume:
1.0 mL Platelet Poor Plasma
Transport & Storage: Temperature/Stability:
90 days Frozen
Rejection Criteria:
Specimens received room temperature or refrigerated • Hemolysis • Thawed
Reference Range:
| Lupus Anticoagulant |
Not detected |
| PTT-LA Screen |
≤40 sec |
| DRVVT Screen |
≤45 sec |
Critical Ranges:
Test Comments:
PTT-LA and dRVVT with Reflex Confirmations
If PTT-LA is >40 seconds, Hexagonal Phase Confirmation will be performed at an additional charge (CPT code(s): 85598).
If Hexagonal Phase Confirmation is positive or weakly positive, Thrombin Clotting Time will be performed at an additional charge (CPT code(s): 85670. If dRVVT is >45 seconds, dRVVT Confirmation will be performed at an additional charge (CPT code(s): 85597).
If dRVVT Confirmation is positive, a dRVVT 1:1 dilution will be performed at an additional charge (CPT code(s): 85613).
Methodology:
Clot Detection
Clinical Significance:
Lupus anticoagulants (LA) are members of a family of antibodies with phospholipid 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.
Documentation:
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.
Custom Panel:
No
PRODUCTION SCHEDULE
Turn Around Time:
2 to 4 days
Days Performed:
Monday, Tuesday, Wednesday, Thursday, Friday
Sites Performed:
Quest - Chantilly
PHL Test Code:
LUPA
EPIC Test Code:
LAB478
Send Out Test Code:
7079
Included Tests:
CPT Coding:
85613, 85730