A 63-year-old female is readmitted to the ward with a history of fever,
anorexia and jaundice. Eleven days prior to this the patient had been
transfused with 4 units of packed cells, as she had been anaemic,
Haemoglobin 8.6 g/dL (11.5 – 16.5 g/d)
Serum total bilirubin 112 μmol/L (1 – 22 μmol/L)
Which of the following investigations is likely to indicate the cause of the
patient’s current condition?
e) Level of