The World Health Organisation (WHO) has approved the first international standard for a human genetic test. WHO hopes that the move, announced on 17 November, will improve the accuracy and quality of laboratory results worldwide for a test that identifies people at high risk of developing blood clots. Establishing the first standard test for an inherited condition is 'an important milestone', according to David Wood of WHO. 'Genetic testing procedures are playing a vital and growing part in clinical medicine', he added.
The test looks for a particular gene mutation called Factor V Leiden, which is responsible for an increased risk of developing blood clots in the veins of the legs (deep venous thrombosis, DVT), lungs (a pulmonary embolism) or, more rarely, elsewhere. Researchers are investigating whether or not there is a link between air travel and the risk of developing DVT, so-called 'economy class' blood clots. A test for Factor V Leiden could eventually help identify travellers most at risk of this condition. Inheriting one copy of the mutation increases the risk of developing a clot by between four and eight times. People who inherit two copies of the mutation may have up to 80 times the usual risk of developing this type of blood clot.
The new standard test for Factor V Leiden was agreed at the 55th session of the WHO Expert Committee on Biological Standardisation (WHO ECBS), which met from 15-18 November in Geneva, Switzerland. The committee is made up of ten experts from academia, industry and national regulatory authorities, as well as 25 advisors. The test was developed by the UK's National Institute for Biological Standards and Control (NIBSC).
WHO says that a recent study estimated that over 700,000 genetic tests were carried out in the European Union in 2002, involving at least 700 laboratories and 900 clinical centres. Worldwide, it estimates that millions of genetic tests are being carried out each year. The ECBS is likely to approve standards for other genetic tests in the future, which WHO says 'will enable prevention and early treatment of genetic disorders, improving quality of life'.