The Hemoccult test is widely used to screen for colorectal cancer. It uses blood derivatives passed in the stool to detect gastrointestinal bleeding.
People testing positive then have a colonoscopy.
In this study, researchers identified 10 healthy volunteers from Bury, England, a region famed for black pudding (a delicacy consisting of congealed pigs' blood, fat, and rusk, encased in a length of intestine).
The study volunteers were below the age of 35 and had no family history of colorectal cancer.
Each participant completed a Hemoccult test requiring 6 specimens to be taken from stools passed over 3 consecutive days.
|After the consumption of black pudding, 4 people tested positive.|
|British Medical Journal|
Following the tests, participants ate a locally produced black pudding.
They then had a further Hemoccult test.
The research team then analyzed the tests at Bury General Hospital.
The team regarded a positive test result as the occurrence of 1 or more positive specimens from the 6 provided.
The researchers found that initially all volunteers returned negative tests.
However, after the consumption of black pudding, 4 people tested positive.
The ingestion of black pudding resulted in a significantly higher proportion of positive Hemoccult test results.
To calculate the effect of this on a population screening program, the authors questioned 100 people about their black pudding consumption.
They found that 63% consumed black pudding on occasion.
Based on these figures, the authors calculate that more than twice the number of people than expected would test positive and would need further investigation.
Dr Stuart Fludger's team concluded that, "Patients should be advised to avoid black pudding during screening".