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

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.