German researchers looked at the issue because screening for colorectal cancer is often carried out in populations in whom use of low-dose aspirin is common.
Low-dose aspirin increases the risk of gastrointestinal bleeding and so concerns have been raised that it may affect the specificity of tests for colorectal cancer.
Dr Hermann Brenner and colleagues from the German Cancer Research Centre in Heidelberg assessed the performance of immunochemical faecal occult blood tests in around 4,000 people.
They found that the use of low-dose aspirin was associated with a markedly higher sensitivity for detecting advanced colorectal neoplasms, with only a slightly lower specificity.
The researchers said the possibility that test performance may be enhanced by temporary use of low-dose aspirin will need to be followed up in large randomised studies.