Question 9.2

The following blood results were obtained from a previously fit and well patient undergoing a prolonged respiratory wean following an episode of severe community acquired pneumonia one month earlier.

Parameter	Patient Value	Adult Normal Range
Haemoglobin	78 g/l	115- 155
Haematocrit	0.20	0.35 - 0.45
Mean Cell Volume	85 fL	80-99
Mean Cell Haemoglobin	28 pg	27 - 33
White Cell Count	15.3 X 10	4.0 - 11.0
Neutrophils	120 x 10⁹/L	1.9 -7.5
Platelets	758 x	150 - 400
Reticulocyte count	40 x IO⁹/L	30- 130
Iron	8 mmol/L•	10-30
Ferritin	798	20 - 450
Transferrin saturation	0.10	0.15 - 0.50
Vitamin BIZ	700 pmol/L	200 - 900
Folate	1 5 nmol/L
C-reactive rotein	210
Albumin	25	35 - 50

Interpret the abnormal results and justify your reasoning. (40% marks)

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College answer

Normochromic normocytic anaemia of chronic disease with on-going inflammation NOT Fe deficiency anaemia because:

Normochromic normocytic anaemia
Low Fe
Transferrin saturation mildly reduced
Raised ferritin
Raised CRP (inflammatory state)

Discussion

The abnormalities are as follows:

Anaemia, which is normocytic and normochromic
Raised CRP, WCC, neutrophil count and platelet count, suggesting an inflammatory response
Low serum iron
High serum ferritin (it is an acute phase reactant)
Normal levels of haematinic vitamins.
Low reticulocyte count, suggesting depressed bone marrow function. In this case the college give you an absolute reticulocyte count, which actually needs to be corrected for the severity of anaemia. The corrected reticulocyte count is adjusted by the haematocrit (it is assumed that the maturation time of circulating reticulocytes is related to the haematocrit), i.e. with a haematocrit of 0.20 the maturation time is 2 days. Thus the corrected reticulocyte count is actually low (40,000/2 = 20,000).

This is consistent with an anaemia of chronic disease, which is usually a microcytic hypochromic affair (i.e MCV and MCH is usually lower in those cases). The reticulocyte count is typically low, which indicates underproduction of red cells. This comes from the review article by Weiss and Goodnough (NEJM, 2005)

For each of these "interpret iron studies" questions, this table ends up in the discussion section:

Interpretation of Abnormal Iron Studies
Condition	MCV	MCHC	Serum iron	Ferritin	Transferrin	Transferrin saturation	TIBC
Iron deficiency anaemia	low	low	low	low	high	<20%	high
Anaemia of 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	high

References

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.

Weiss, Guenter, and Lawrence T. Goodnough. "Anemia of chronic disease." New England Journal of Medicine 352.10 (2005): 1011-1023.

Koepke, J. F., & Koepke, J. A. (1986). Reticulocytes. Clinical & Laboratory Haematology, 8(3), 169–179.

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