Rescreening of a group at high risk for colorectal neoplasia using immunochemical tests for faecal occult blood. 
The results of a screening programme for colorectal neoplasia in a high risk group using an immunochemical test for blood has been reported recently.  This test is known as the faecal human haemoglobin (FHH) test.  This paper reports the results of rescreening this group after an interval of 1-2 years.  The FHH test was compared with a paper disc method.  All individuals with positive tests were investigated and those with negative tests were offered investigation.  The results confirm the value of the FHH test in screening a high risk group: 19 individuals in 1,153 participants were found to have a significant neoplasm (1.6%).  The predictive value of the test for a significant neoplasm was 42%.  A false negative rate of 2.6% was found, all lesions being benign.  It appears to be more reliable than the paper disc method but the differences do not reach statistical significance.  The FHH test is recommended for screening the general population over the age of 40 years, with rescreening annually.