MSFinals-2407
John, a 35-year-old Caucasian man visited his doctor with a range of symptoms. He reported feeling feverish on and off for the past few months, experiencing fatigue, unintentional weight loss of around 3kg, and general muscle aches and pains. He was not taking any medication. Upon examination, his doctor found no abnormalities in his observations or physical examination. The doctor ordered a full blood count, which showed the following results:
– Hb 112g/L Male: (130 – 180)
– Platelets 200 * 109/L (150 – 400)
– WBC 3.8 * 109/L (4.0 – 11.0)
– Lymphocytes 2.8 * 109/L (1.0 – 4.5)
– Mean corpuscular volume 92 fL (76 – 98)
– Mean corpuscular haemoglobin 31 pg (27 – 32)
– Ferritin 40 ng/mL (20 – 230)
Based on these results, the doctor suspects that John may have systemic lupus erythematosus (SLE) and orders further blood tests. Which test, if positive, would best indicate that John is likely to have this condition?