Faecal haemoglobin concentrations by gender and age: implications for population-based screening for colorectal cancer

Abstract Background: Faecal immunochemical tests (FIT) are becoming widely used in colorectal cancer screening. Estimation of faecal haemoglobin concentration in a large group prompted an observational study on gender and age. Methods: A single estimate of faecal haemoglobin concentration was made using quantitative automated immunoturbidimetry. Potential reference intervals were calculated for men and women and for age quintiles according to the Clinical and Laboratory Standards Institute Approved Guideline. The percentages of positive results were calculated at a number of concentrations. The percentages of individuals who fell into different risk groups were assessed. Results: The 97.5 percentiles, potential upper reference limits, were 519 ng haemoglobin/mL (90% CI: 468–575) for men and 283 ng haemoglobin/mL (90% CI: 257–316) for women. Concentrations increased with age in both genders. Decision limits have advantages over reference intervals. At any cut-off concentration, more men are declared positi...