Hemochromatosis: Likelihood Ratios

Introduction: Hemochromatosis is a condition in which the body accumulates too much iron. Hereditary hemochromatosis, most commonly caused by the C282Y mutation in the HFE gene, results from increased gut iron absorption. Acquired hemochromatosis can be caused by many blood transfusions. Hemochromatosis principally affects the liver, pancreas, and heart.

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Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
C282Y Homozygotes	38%	that develop actual hemochromatosis. 10-33% may develop actual morbidity. Ann Intern Med. 2006 Aug 1;145(3):209-23. PMID: 16880463
Patients with hemochromatosis	82%	that have the C282Y mutation in HFE gene: 72.8-91.3% J Med Genet. 2008 Aug;45(8):513-8. PMID: 18310265
Primary Care Population	0.6%	for hereditary hemochromatosis Ann Intern Med. 2005 Oct 4;143(7):522-36. PMID: 16204165
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The likelihood ratios of findings for Hemochromatosis are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] Unbound Iron Binding Capacity	+ 0 -	100	0
UIBC <= 25 in men - for detecting C282Y homozygotes Study: Hepatology. 2000 May;31(5):1160-4 PMID: 10796893
[ + ] Transferrin, high saturation	+ 0 -	20	0
sat >= 46% Study: Hepatology. 2000 May;31(5):1160-4 PMID: 10796893
[ + ] Liver MRI T2 Relaxation	+ 0 -	inf	0.1
compared to quantitative liver iron content Study: Ann N Y Acad Sci. 2005;1054:379-85. PMID: 16339686
[ + ] C282Y Homozygosity	+ 0 -	68.3	0.2
For a diagnosis of hereditary hemochromatosis, in patients diagnosed with hemochromatosis. Note that there is variable penetrance of the mutation, namely not all patients with the mutation will have hemochromatosis. Study: J Med Genet. 2008 Aug;45(8):513-8. PMID: 18310265
[ + ] Unbound Iron Binding Capacity	+ 0 -	18.3	0.3
UIBC <= 28 in women - for C282Y homozygotes Study: Hepatology. 2000 May;31(5):1160-4 PMID: 10796893
[ + ] Liver Iron Content	+ 0 -	3.6	0.3
iron content > 236 mcmol/g dw for cirrhosis, in a population of asymptomatic C282Y homozygotes. Study: Arch Intern Med. 2006 Feb 13;166(3):294-301. PMID: 16476869
[ + ] Transferrin, high saturation	+ 0 -	12.8	0.4
sat >= 46% Study: Hepatology. 2000 May;31(5):1160-4 PMID: 10796893