Table Investigations for thrombophilia. Cases 1 and 2 had evidence of lupus anticoagulant, as demonstrated by a prolonged dilute Russell's viper venom time (DRVVT) which corrected on the addition of platelet phospholipid (DRVVT(PN)). Case 1 had, in addition, raised IgG anticardiolipin antibodies and case 3 a reduction in free protein S. APCR = activated protein C resistance.
| Case 1 | Case 2 | Case 3 | Normal range | |
|---|---|---|---|---|
| Protein C (IU/ml) | 0.96 | 1.00 | 1.37 | 0.67–1.38 |
| Protein S antigen, total (IU/ml) | 1.02 | 1.32 | 0.81 | 0.64–1.54 |
| Protein S antigen, free (IU/ml) | 0.71 | 1.34 | 0.55 | 0.61–1.43 |
| Antithrombin (IU/ml) | 0.89 | 1.02 | 0.92 | 0.80–1.20 |
| Anticardiolipin IgG (g/l) | 55.4 | 1.9 | <5.0 | <8.0 |
| Anticardiolipin IgM (mg/l) | 0 | 0.2 | 8.3 | <11.0 |
| DRVVT ratio | 1.24 | 1.13 | 0.86 | 0.90–1.09 |
| DRVVT(PN) ratio | 1.12 | 1.03 | ||
| Kaolin clotting time ratio | 0.8 | 1.04 | 1.03 | <1.10 |
| APCR | 2.6 | >3.6 | not done | >2.0 |
| Factor V Leiden | negative | negative | negative | negative |