As the odds ratio for a single BCAT1 positive PCR replicate representing a false-positive (i.e. a case without neoplasia) compared to a true-positive (i.e. a case with CRC) was 17.7 (95% CI6.6–43.3), p < 0.0001), a ‘BCAT1 replicate rule’ for assay positivity requiring at least two positive BCAT1 replicates was evaluated. The gene discussed is BCAT1; the disease is neoplasm.