As mentioned in TEC 1 the screening process consists of different stages depending on whether a population-based systematic screening programme or various opportunistic screening practices are implemented.

Population-based systematic screening programme

For the National Health Services (NHS) AAA Screening Programme {5} in England standard operating procedures (SOP) are designed to inform and assist screening leads, strategic health authorities and other key stakeholders to establish and implement a new AAA population-based screening programme. The necessary elements of a screening programme, the screening pathway and quality assurance processes, and requirements for programmes are described. These SOPs state that the minimum population for selection of a population-based screening programme is 800,000 patients with detected AAA, which could be treated in a suitable medical centre. In the NHS AAA Screening Programme men are automatically invited by letter in the year they turn 65 years and men who are older than 65 years, and who have not previously been screened or treated for an abdominal aortic aneurysm, can opt in through self-referral direct to the screening programme (see CUR). The invitation comes from the local screening office and not from the general practitioner. {5}

In Sweden the population-based screening programme screens a defined healthy population (with defining a risk profile/an eligible population) by an invitation to a screening programme. Eligible people are invited by e-mail by the Register of Total Population managed by Statistic Sweden including age and gender. {8}

In the USA patients are eligible for population-based AAA screening if they have a family history of AAA, and/or if they are a man, age 65 to 75 years who has smoked at least 100 cigarettes in his lifetime and has never had an AAA ultrasound screening paid for by Medicare. {9}

Various opportunistic screening practices

For various opportunistic screening practices no specified population is defined for which AAA screening should be used. Usually, persons at risk are most likely adverted by assignments by their general practitioners.