The main indications of venous thromboembolism genetic test are:
- commencing a hormonal contraception or hormone replacement therapy in a woman at risk group (patient or her close family has a history of thrombotic diseases, there is known existence of pro thrombophilic gene in the family)
- several unsuccessful artificial fertilization (IVF) attempts
- occurrence of venous thrombosis during pregnancy or woman taking oral contraceptives
- prenatal complications (recurrent miscarriages, pre-eclampsia or miscarriage)
- family history of venous thrombosis
- presence of pro venous thromboembolism gene in the family
- venous thrombosis <50 years of age
- heart attack on <50-year old woman who smoke
Venous thromboembolism (VTE) includes a deep vein thrombosis and pulmonary embolism.
Venous thromboembolism often occurs when several risk factors (genetic and acquired during life) occur simultaneously.
The most important acquired risk factors are considered to be major surgery and trauma. Moderate risk factors are considered to be pregnancy, taking birth control or HRT tablets, puerperium and tumors. Minor risk factors are considered to be immobilization/ immobilization of a limb in a forced position or paralysis due to prolonged air travel or other reasons.
Congenital or genetic factors which contribute to formation of venous thromboembolism are a mutation in Factor V Leiden, prothrombin G20210A mutation of the MTHFR gene and the C677T and A1298C mutations.
Table 1. Overview of genetic risk factors of venous thromboembolism:
| Genetic marker | Frequency | Risk |
| Faktor V Leiden | ~ 2.7% in Europe (0 – 7% depending on area), 3% in Estonia | Heterozygotes have 3-7 times greater risk of having VTE, homozygotes 50-100 times greater risk of VTE |
| Prothrombin G20210A | 1 – 8% in Europe, 3.3% in Estonia | 2-5 times greater risk of VTE heterozygotes, approximately 10-fold increased risk for homozygotes |
| MTHFR C677T | ~ 35% of Europeans are heterozygotes, homozygotes 12% | 2 to 3 times higher risk of VTE for homozygotes |
| MTHFR A1298C | 9-20% in all major ethnic groups | increased risk of VTE for heterozygotes if occurs with the heterozygous C677T mutation |
In case of existence of higher congenital VTE risks the following precautions should be subjected:
- Opt instead for hormonal contraceptives to prevent pregnancy by another means
- Consult with a doctor about hormone replacement therapy tactics with menopause
- Consult with a physician before operation regarding taking blood thinning medications
- Consult with a doctor if it is necessary to take blood-thinning medications during pregnancy and postpartum period
- Quit smoking
- Regular exercise to stimulate the blood flow and loose excessive weight
- During long trips to drink enough water and if possible, to move around in the meantime
With presence of genetic risk factors a medical consultation with skilled physician is needed to evaluate the risk of thrombosis and to assess the need for preventive treatment. It might be recommend for other members of the family to have a genetic counseling as well and to have the test in regard with present genetic changes.
The results will be ready within 5-7 working day.
Venous thromboembolism genetic risk assessment test costs 250 euros to which will be added to the price of a consultation with gynecologist and ultrasound.