Lupus anticoagulants (are antiphospholipid antibodies (PSA), the screening of which is done by demonstrating prolongation of coagulation times corrected by the intake of phospholipids (PL).

Learned societies (ISTH, CLSI) thus recommend, for the research of LA, to carry out initially two screening tests with a low concentration in PL: a time of diluted Russell viper venom (DRVVT) as well as a time activated partial thromboplastin (TCA). If one of these screening tests is positive, it is recommended to perform a second confirmation test using the same principle (DRVVT or TCA) and containing a higher concentration of PL.

The current LA screening method at the Hematology Laboratory of Strasbourg University Hospital includes: a pair of DRVVT screening / confirmation (STA-Staclot DRVV Screen and Confirm, Diagnostica Stago, France) and a screening TCA (PTT-A , Diagnostica Stago, France).

This study aims to compare with the current method of the investigators a pair of TCA screening / confirmation (Cephen LS / Cephen, Hyphen Biomed, France).

Inclusion criteria:

• Major subject
• blood sample already analyzed in the laboratory as part of the treatment by the reference method
• Patient who did not express his opposition to the reuse of his data and his blood sample for the technical study.

Exclusion criteria:

• Minor patient
• Patient under curatorship, guardianship or legal protection
• Patient who expressed his opposition to the use of his data
• Insufficient sample

Major subject with blood sample already analyzed in the laboratory as part of the treatment by the reference method