20.08
A 70-Year-Old Man with Fever, Fatigue and Dyspnoea of Recent Onset
Again my
colleague had already done the diff, but she pays for it and I am in no way
complaining. I felt the diff was 98% lymphocytes and 2% neutrophils
I felt the
diagnosis was CLL (Chronic lymphocytic leukemia) with a haemolytic anaemia
The
obvious next step was to perform direct antiglobulin test (DAT), a reticulocyte
count and lymphocyte subtyping
To answer
the questions:
1 Comment
on the results of the erythrocyte indices.
The MCV is
very raised and haemoglobin very low.
The red
cell indices show an implausibly low MCHC suggesting something awry in the red
cell indices measurements/calculations.
2 In view
of all the laboratory findings, how do you explain the abnormalities of the
erythrocyte indices?
The RBC
histogram shows that a population of huge (relatively) cells is present.
Red cells
and white cells are counted together by the impedance technique which does not
cause issues at usual levels of white cell count. However when the white cells
count is high it can cause an erroneous overestimation of the red cell
count and mean cell volume and consequently haematocrit.
Thus the
MCHC is calculated wrongly (i.e. very low)
3 Which
results of the blood count do you think are really informative? Would you
validate them?
These red
cell results are not accurate (i.e. wrong). The sample should be diluted and
re-analysed.
4 What is
the most likely mechanism of this patient’s anaemia? (The answer to this
question must not be repeated in the diagnostic hypotheses.)
The
presence of polychromasia and spherocytes suggest a possible haemolytic
anaemia.
I did ok… not sure I understood the last question though...
