ABSTRACT
Hereditary predispositions to VTE (thrombophilias) Blanket screening by any blood test is not justifiable – not only would the cost be prohibitive but in terms of the occurrence of actual disease events there are just too many false negatives and positives. Almost the only indication for screening is a strong family history of one or more siblings or parents having had a spontaneous VTE under the age of 45. This justifies testing for the genetic predispositions, including Factor V Leiden (the genetic cause of activated protein-C resistance). Even if all the results are normal, the COC remains WHO 2. The woman cannot be totally reassured, since by no means all the predisposing abnormalities of the complex haemostatic system have yet been characterized. Such an individual, like any Pill-taker with one VTE-linked relative contraindication (3rd or 4th columns of Table 5), should normally receive a LNG/NET Pill, unless there is a clear therapeutic indication for COC therapy, in which case extra therapeutic benefits may be judged to outweigh any expected extra risks.
