Advertisement

Assessment of Normative Range and Deriving Cut-Off Values for Lupus Anticoagulant Testing: An Experience from a Tertiary Care Center in Southern India

  • Arikrishnan Ramaraj
  • Vir Singh Negi
  • Rakhee KarEmail author
Short Communication
  • 3 Downloads

Abstract

Lupus anticoagulant (LA) testing is a demanding laboratory test. The most common among recommended tests for LA are dilute Russell viper venom time (dRVVT) and LA sensitive activated partial thromboplastin time (LA-aPTT). Although integrated test systems come with manufacturer assigned cut-off, but according to guidelines cut-off should be locally-derived. This study was carried out to find normative range of LA using LA-aPTT and dRV VT tests in south Indian population (n = 100) and using locally derived cut-off values to interpret patient samples (n = 152) in a one-year study period. Cut-off (mean+2.3 SD) for aPTT, LA-aPTT, dRVVT screen and dRVVT confirm assays were 37.5, 45.7, 45.5 and 41.3 s and for normalized ratio and percentage correction of ratio were 1.16 and 15.8% respectively. Among patients, 25 (16.4%) were positive of whom 14 were positive by normalized ratio, seven by LA-aPTT and four were positive by both. Four additional patients could be identified using local cut-off. While the specificity of all screening tests was high, sensitivity of only dRVVT screen was high. All testing laboratories should attempt to derive normative range and locally-derived cut-off. While dRVVT is a good screening test with high sensitivity, however combining LA-aPTT offers advantage of picking up cases negative by dRVVT.

Keywords

Lupus anticoagulant Cut-off Locally-derived Normative range dRVVT LA-aPTT Normalized ratio 

Notes

Funding

JIPMER intramural grant in support of MSc-MLT dissertation.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflicts of interest.

Ethical Approval

Informed consent was taken from all the study participants and the study was approved by the Institute Ethics Committee.

References

  1. 1.
    Moore GW (2014) Recent guidelines and recommendations for laboratory detection of lupus anticoagulants. Semin Thromb Hemost 40(2):163–171CrossRefGoogle Scholar
  2. 2.
    Pengo V, Tripodi A, Reber G, Rand J, Ortel T, Galli M et al (2009) Update of the guidelines for lupus anticoagulant detection. J Thromb Haemost 7:1737–1740CrossRefGoogle Scholar
  3. 3.
    Keeling D, Mackie I, Moore GW, Greer IA, Greaves M (2012) Guidelines on the investigation and management of antiphospholipid syndrome. Br J Haematol 157:47–58CrossRefGoogle Scholar
  4. 4.
    CLSI. Laboratory testing for the lupus anticoagulant; Approved Guideline. (2014) CLSI document H60-A, Wayne, P.A: Clinical and Laboratory Standards Institute.Google Scholar
  5. 5.
    Saldarriaga M, Lozada M, Lopez G (2014) Determination of cut-off values in healthy donors for lupus anticoagulant detection protocol in the laboratorio medico echavarrria, according to the international guidelines. Pathol clin med lab 61:145–149Google Scholar
  6. 6.
    Gardiner C, Mackie I, Malia R, Jones D, Winter M, Leeming D et al (2008) The importance of locally derived reference ranges and standardised calculation of dilute Russell's viper venom time results in screening for lupus anticoagulant. Br J Haematol 111:1230–1235CrossRefGoogle Scholar

Copyright information

© Indian Society of Hematology and Blood Transfusion 2019

Authors and Affiliations

  • Arikrishnan Ramaraj
    • 1
  • Vir Singh Negi
    • 2
  • Rakhee Kar
    • 1
    Email author
  1. 1.Department of PathologyJawaharlal Institute of Postgraduate Medical Education and ResearchPuducherryIndia
  2. 2.Department of Clinical ImmunologyJawaharlal Institute of Postgraduate Medical Education and ResearchPuducherryIndia

Personalised recommendations