Research has revealed that the bowel cancer screening test is significantly more likely to identify cancerous changes in winter than it is in summer.
As this is the first research to examine the impact of temperature on the screening test's accuracy, the authors believe it could have important implications for interval cancers - malignancies that develop between screenings.
Bowel cancer screening involves detecting blood hidden in a stool sample - a procedure known as the faecal occult blood test, or FOBT.
Researchers examined the impact of ambient temperature on the performance of FOBTs in the Italian national screening programme in Florence over several different seasons.
This included temperature variations between faecal sampling and the return of the test sample - on average around seven days, as well as the time in the laboratory refrigerator, at an average of around four days.
In total, just under 200,000 FOBT results were assessed for haemoglobin (Hb) levels - the protein in blood which colours it red. They revealed that Hb levels were significantly lower in the summer months.
Average levels were 27.6 in spring; 25.2 in summer; 29.2 in autumn; and 29.5 in winter.
The research was published online in the journal Gut.