PAI-1 (Plasminogen Activator Inhibitor-1) Genotype

This test looks for a common genetic variant in the SERPINE1 gene, known as the PAI-1 -844 G>A variant. This gene provides instructions for a protein called plasminogen activator inhibitor-1 (PAI-1), which helps regulate the breakdown of blood clots. The variant can influence how much PAI-1 the body produces, which in turn may affect the balance between forming and dissolving clots. It is one of several genetic factors that can contribute to a tendency to clot.

What it can help assess

• Inherited clotting tendency: the PAI-1 variant is one of several genetic factors that can influence the body's ability to break down clots
• Understanding personal or family history: particularly where there is a personal or family history of blood clots
• Building a fuller genetic picture: it is usually assessed alongside other clotting-related genetic markers rather than on its own

Understanding the results

You inherit two copies of the SERPINE1 gene, one from each parent. This test can identify whether you carry no copies, one copy, or two copies of the -844 G>A variant. The significance of the result depends on which combination is present and how it fits with your other clotting markers and history.

Interpreting your result

This is a genetic test, and the results are provided to the clinician who referred you. The PAI-1 variant is common in the general population, and on its own it is considered a modest factor, so its meaning depends heavily on the wider context. Your referring clinician will interpret your result alongside your personal and family history and any other clotting markers, and advise on what it means and any next steps. Where appropriate, genetic counselling can help explain what a result means for you and your family.

Why it matters

Understanding your inherited clotting factors can contribute to a fuller picture of your clotting risk, particularly where there is a personal or family history of clots. As this is one of several contributing factors, it is most useful as part of a wider assessment rather than in isolation.