Example of a β2GPI-dependent LAC and a β2GPI-independent LAC
. | Coagulation times . | . | Ratios of coagulation time of patient to normal pool plasma . | . | Differences in ratio between 25 μM CL and 0 μM CL . | ||
|---|---|---|---|---|---|---|---|
| Plasma . | 0 μM CL . | 25 μM CL . | 0 μM CL . | 25 μM CL . | . | ||
| Normal pool plasma | 40.0 | 41.7 | NA | NA | NA | ||
| Patient with β2GPI-dependent LAC | 106.3 | 88.8 | 2.66 | 2.13 | -0.53 | ||
| Patient with β2GPI-independent LAC | 69.7 | 73.5 | 1.74 | 1.76 | 0.02 | ||
. | Coagulation times . | . | Ratios of coagulation time of patient to normal pool plasma . | . | Differences in ratio between 25 μM CL and 0 μM CL . | ||
|---|---|---|---|---|---|---|---|
| Plasma . | 0 μM CL . | 25 μM CL . | 0 μM CL . | 25 μM CL . | . | ||
| Normal pool plasma | 40.0 | 41.7 | NA | NA | NA | ||
| Patient with β2GPI-dependent LAC | 106.3 | 88.8 | 2.66 | 2.13 | -0.53 | ||
| Patient with β2GPI-independent LAC | 69.7 | 73.5 | 1.74 | 1.76 | 0.02 | ||
To discriminate between a β2GPI-dependent LAC and a β2GPI-independent LAC we added 25 μL PTT-LA reagent, 50 μL patient plasma (mixed 1:1 with normal pool plasma), and 25 μL of different concentrations cardiolipin (0, 25, 50, 100, 200 μM) to a KC-10 micro coagulometer (Amelung, Lemgo, Germany). After 3 minutes of incubation at 37°C, coagulation was initiated by the addition of 50 μL CaCl2 and clotting time was measured. A LAC was considered β2GPI dependent when the ratio of coagulation times of patient plasma and normal pool plasma was decreased by at least 0.05 with addition of cardiolipin vesicles at a concentration of 25 μM cardiolipin vesicles.
CL indicates cardiolipin; and NA, not applicable.