This topic has appeared with increasing frequency in recent exam papers:
The best published resources for this topic would have to be this article by Hawkins et al (2014) and a free online guide to laboratory diagnosis of iron deficiency published by Dr Gross at www.iron.sabm.org. The candidate with infinite time resource may be interested in this reporting standards statement from the Australian Royal College of Pathologists. For
In brief, this complex topic can be reduced to a table.
Condition | MCV | MCHC | Serum iron | Ferritin | Transferrin | Transferrin saturation |
TIBC |
Iron deficiency anaemia | low | low | low | low | high | <20% | high |
Anaemia of inflammation (chronic disease) | low | low | low | normal | low | normal | low or normal |
Acute phase response | normal | normal | low | high | low | low | low |
Iron overload | normal | normal | high | high | normal | high | low |
We have about 3.7 grams of iron in our body, painstakingly gathered from iron in our diet. The majority of it (about 2.5 grams) is locked inside the hemoglobin in our blood, being essential to the transport of oxygen. Another few tenths of a gram are found in myoglobin, which also assists in oxygen management. A remarkably small amount--about 0.02 g--is distributed between the many different proteins that transfer electrons, such as the proteins of the oxidative phosphorylation electron transport chain that create most of our cellular ATP supplies. The rest, about a gram, is stored inside ferritin to fulfil future needs.
In Question 22.1 from the second paper of 2016, the college wanted only one specific diagnosis to explain a serum ferritin level of 120,000. Not to be outdone, in Question 24.1 from the first paper of 2020 and Question 18 from the second paper of 2021, the ferritin level was 181,910 IU/L. There is a whole series of possibilities for a high ferritin, and an article by Moore et al (2013) is a good resource for these differentials. The authors sifted though two years worth of iron studies from a major tertiary hospital, and came up with a list of the most common conditions (malignancy was the top culprit). Approximately twenty years previously, another group did much the same thing (Lee et al, 1995). The findings generated by these authors have been combined into the list offered below:
All this considered, the only cause of a truly insane ferritin level is still haemophagocytic syndrome. The causes of this rare disease can be found in the review article by Gritta Janka (2008).
Congenital:
Acquired causes
Moore Jr, Charles, Michelle Ormseth, and Howard Fuchs. "Causes and significance of markedly elevated serum ferritin levels in an academic medical center." JCR: Journal of Clinical Rheumatology 19.6 (2013): 324-328.
Lee, Mark H., and Robert T. Means. "Extremely elevated serum ferritin levels in a university hospital: associated diseases and clinical significance." The American journal of medicine 98.6 (1995): 566-571.
Hawkins, Stephen F., and Quentin A. Hill. "Diagnostic Approach to Anaemia in Critical Care." Haematology in Critical Care: A Practical Handbook (2014): 1-8.
IRON STUDIES STANDARDISED REPORTING PROTOCOL - RCPA, 2013
Hearnshaw, Sarah, Nick Paul Thompson, and Andrew McGill. "The epidemiology of hyperferritinaemia." World journal of gastroenterology 12.36 (2006): 5866. - ! WARNING ! this link will download the whole September issue, with the potential to fatally clog your internet hole.
Janka, Gritta E. "Hemophagocytic syndromes." Blood reviews 21.5 (2007): 245-253.