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Lupus Anticoagulant, Plasma

Test ID: NSCI

Test

Aliases/Synonyms

LA; Non-Specific Inhibitor; NSI; Non Specific Inhibitor; Circulating Anticoagulant; Phospholipid Antibody; Antiphospholipid; APL; Diluted Russell Viper Venom Time

Method

Lupus Anticoagulant-Sensitive APTT Reagent/RVV Time Test

Method Description

LA testing is done by optical clot detection methods, using the HemosIL Silica Clotting Time and dRVVT Screen and Confirm reagents on the ACL TOP analyzer.

Report Includes

INR; Prothorombin Time; Thrombin time; Fibrinogen; APTT; Lupus Anticoagulant Interpretation; SCT; DRVVT

Specimens

Plasma

Clinical Utility

Testing is done in accordance with recent International Society on Thrombosis and Haemostasis (ISTH) guidelines on lupus anticoagulant (LA), that recommend:

  1. assessment of the PT, APTT, thrombin clotting time (TCT) and fibrinogen as part of LA test panel to evaluate for potential interference from anticoagulants or a coagulopathy
  2. testing for LA by a LA-sensitive APTT and a dilute Russel Viper Venom Time (dRVVT)
  3. mixing and confirmatory tests (for phospholipipd dependence) if the LA screening tests are abnormal.

Test Location

Laboratory Reference Centre, 237 Barton Street E, Hamilton ON L8L 2X2

Test Version

19-Jan-2024

Specimen

Specimens

Plasma

Collection Containers

Blue top (3.2% buffered citrate)

Sample Volume

1 mL

Collection & Handling

Collection Instructions

Ensure full draw with 9:1 ratio (9 parts blood to 1 part anticoagulant).

Handling Information

Prepare platelet-poor plasma (double spun) within 4 hours of collection and freeze immediately. Store and send frozen.

Stability

Ambient Unacceptable
Refrigerated Unacceptable
Frozen 60 days

Additional Stability Information

Stable up to twelve months at -70°C

Rejection Criteria

Specimen Not frozen

Test Version

19-Jan-2024

Performance / Interpretation

Method

Lupus Anticoagulant-Sensitive APTT Reagent/RVV Time Test

Method Description

LA testing is done by optical clot detection methods, using the HemosIL Silica Clotting Time and dRVVT Screen and Confirm reagents on the ACL TOP analyzer.

Turnaround Time

9 days

Results

Name Units Reference Range Conversion Factor
INR
  • 0.8 - 1.1
Prothrombin Time (PT) in PPP by Coagulation Assay s
  • 9.4 - 12.5
Thrombin Time s
  • 12 - 19
Fibrinogen (g/L) in PPP by Coagulation Assay g/L
  • 2.0 - 3.9
APPT s
  • 25 - 37
Lupus Anticoagulant Interpretation
SCT Screen
  • ≥ 1.21
SCT Confirm
Only reported when screen is abnormal
SCT SC Ratio
  • ≥ 1.21
Only reported when screen is abnormal
SCT MIX
  • ≥ 1.15
Only reported when screen is abnormal
DRVVT screen
  • ≤ 1.23
    Updated reference range effective January 31, 2024: ≤ 1.26
DRVVT Confirm
Only reported when screen is abnormal
DRVVT SC Ratio
  • ≤ 1.17
    Updated reference range effective January 31, 2024: ≤ 1.21
Only reported when screen is abnormal
DRVVT Mix
  • ≤ 1.11
    Updated reference range effective January 31, 2024: ≤ 1.13
Only reported when screen is abnormal

Test Location

Laboratory Reference Centre, 237 Barton Street E, Hamilton ON L8L 2X2

Test Version

19-Jan-2024

Interface / Setup

HL7 Interface Codes

Order Code Result Codes Units
NSCI 64493INR
64494PROTHROMBIN TIME (PT) IN PPP BY COAGULATION ASSAY s
64481THROMBIN TIME s
7395FIBRINOGEN (G/L) IN PPP BY COAGULATION ASSAY g/L
64504APTT s
64503LUPUS ANTICOAGULANT INTERPRETATION
64495SCT SCREEN
64496SCT CONFIRM
64497SCT SC RATIO
64498SCT MIX
64499DRVVT SCREEN
64500DRVVT CONFIRM
64501DRVVT SC RATIO
64502DRVVT MIX

Test Version

19-Jan-2024