Addition of cardiolipin in APTT-based LAC assay
. | Coagulation time . | . | Ratio, patient to normal pool . | . | Difference, ratio 25 μm CL—ratio 0 μm CL . | ||
|---|---|---|---|---|---|---|---|
| Plasma . | 0 μm CL . | 25 μm CL . | 0 μm CL . | 25 μm CL . | . | ||
| Normal pool plasma | 37.4 | 38.6 | NA | NA | NA | ||
| Plasma with β2GPI-dependent LAC | 69.0 | 57.0 | B0/C0 = 1.84 | B25/C25 = 1.48 | -0.36 | ||
| Plasma with β2GPI-Independent LAC | 72.5 | 79.2 | A0/C0 = 1.91 | A25/C25 = 2.05 | 0.14 | ||
. | Coagulation time . | . | Ratio, patient to normal pool . | . | Difference, ratio 25 μm CL—ratio 0 μm CL . | ||
|---|---|---|---|---|---|---|---|
| Plasma . | 0 μm CL . | 25 μm CL . | 0 μm CL . | 25 μm CL . | . | ||
| Normal pool plasma | 37.4 | 38.6 | NA | NA | NA | ||
| Plasma with β2GPI-dependent LAC | 69.0 | 57.0 | B0/C0 = 1.84 | B25/C25 = 1.48 | -0.36 | ||
| Plasma with β2GPI-Independent LAC | 72.5 | 79.2 | A0/C0 = 1.91 | A25/C25 = 2.05 | 0.14 | ||
Plasmas of 2 patients were diluted 1:1 with normal pool plasma and incubated with different concentrations of cardiolipin and reagent (Diagnostica Stago). As a reference we performed the same assay with normal pool plasma. An LAC was characterized as β2-GPI dependent when the ratio of patient plasma divided by normal plasma decreased by at least 0.05 at 25 μM cardiolipin compared with no addition of cardiolipin. Coagulation was initiated by the addition of CaCl2, and clotting time was measured.
NA indicates not applicable.