Colon cancer screening test less likely to detect cancer in summer compared to winter

A commonly used screening test to diagnose colon cancer is a simple test called fecal occult blood testing (FOBT).  A new Italian study published this week suggests that the test results may be less accurate when outside temperatures are high compared to low ambient temperatures.  This study suggests that FOBT colon cancer screening is more likely to detect cancer if performed in the colder seasons as opposed to the summertime. 

The difference was significant, with screening tests done in the summer being 17 percent less accurate than those done in the winter.  For advanced cancers, there was a 13% lower accuracy level for tests done in the summer compared to winter.  The researchers believe that the body's lower concentrations of hemoglobin in warmer weather accounts for the results.