Prof John Olynyk, Gastroenterologist, Beaconsfield

Clinicians are often on the lookout for HFE Haemochromatosis – most often flagged with family history, elevated iron studies or typical genetic test results. A new Australian research study has demonstrated that the commonest blood test ordered in Australia (the Full Blood Count – FBC) may also reveal otherwise unsuspected HFE Haemochromatosis.

ED: Haemochromatosis is common but often missed. Testing may change that, starting with the FBC.

Shortly after discovery of the HFE gene in 1996 (HFE stands for HighFe; the HFE gene is on the short arm of chromosome 6 at location 6p21.3), an American study reported observations of elevated haematological parameters in those with the disorder. The recent Australian study, not only demonstrates similar findings, but shows that elevated mean cell volume (MCV) and mean cell haemoglobin (MCH) values are present in treated, untreated and asymptomatic young adult HFE Haemochromatosis people.

The study clearly recommends how to “value add” to the clinical utility of the FBC by suggesting who to evaluate further, depending on the MCV and MCH results (Figure 1). These findings are being incorporated into the Primary Health Care Pathways in each state, and are already in use in Western Australia.

Subjects of Northern European ancestry with MCV >94 fl or MCH >32.2 pg are at 30-fold enriched prevalence compared to the general population. This is the same enrichment as seen within families of known HFE Haemochromatosis subjects, perhaps newly discovered; up to 62% of all HFE Haemochromatosis subjects in Australia present above these cut-off values – they should be considered for further assessment of HFE Haemochromatosis.

Conversely, less than 10% of all HFE Haemochromatosis subjects are in the group of individuals with MCV < 90 fl or MCH < 31 pg. For those with values in between, the current standard of care recommendations apply.

Key Messages

  • The possibility of HFE Haemochromatosis can be raised by a Full Blood Count.
  • A MCV >94fl and MCH >32.2pg can pick up 62% of all HFE Haemochromatosis Australians.
  • For those not picked up on a FBC, Haemochromatosis may be indicated through clinical suspicion, family history, elevated serum iron studies or documented HFE C282Y homozygosity.

Author competing interests: nil relevant disclosures.

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