Comparison of population screening strategies for haemochromatosis
Phenotypic (sequential visits) | Phenotypic/genotypic (sequential visits) | Phenotypic/genotypic (one step) | Genotypic/phenotypic (one step) | |
Initial test | TS or UIBC | TS or UIBC | TS or UIBC | C282Y |
Secondary tests | Returns for fasting TS then ferritin | Returns for fasting TS then ferritin followed by C282Y | Ferritin on original sample followed by C282Y | Ferritin on original sample |
Liver biopsy | All | Selected cases (liver dysfunction, atypical genetic test) | Selected cases (liver dysfunction, atypical genetic test) | None |
Overdiagnosis | Alcoholic liver disease, chronic viral hepatitis | No | No | Detects non expressing homozygotes |
Underdiagnosis | Will exclude homozygotes with TS <45% and those that do not return for fasting TS | Will exclude homozygotes with TS <45% and those that do not return for fasting TS | Will exclude homozygotes with TS <45 % or UIBC >28 μmol/l | Will exclude non-C282Y haemochromatosis |
Age dependent | Yes | Yes | Yes | No |
Detects iron deficiency | Yes | Yes | Yes | No |
Cost considerations | Cost of liver biopsy | Cost of lost homozygotes that do not return for fasting TS | More C282Y and ferritin tests but fewer homozygotes missed | Cost of initial genetic test |
TS, transferrin saturation; UIBC, unbound iron binding capacity.