A man visited his GP complaining of constant fatigue, feeling cold all the time, and unexplained weight gain.
He had blood tests to investigate the cause of these symptoms.
The results of the blood tests are shown in the table below.
| Blood test | Man's result | Normal range |
|---|---|---|
| TSH level | 12.4 mU/l12.4 \text{ mU/l}12.4 mU/l | 0.4 to 4.5 mU/l0.4 \text{ to } 4.5 \text{ mU/l}0.4 to 4.5 mU/l |
| Thyroxine level | 5.8 pmol/l5.8 \text{ pmol/l}5.8 pmol/l | 9.0 to 21.0 pmol/l9.0 \text{ to } 21.0 \text{ pmol/l}9.0 to 21.0 pmol/l |
| White blood cell count | 6.8 × 109 /l | 4.0 to 11.0×109/l4.0 \text{ to } 11.0 \times 10^9 \text{/l}4.0 to 11.0×109/l |
| Calcium level | 2.30 mmol/l | 2.15 to 2.55 mmol/l2.15 \text{ to } 2.55 \text{ mmol/l}2.15 to 2.55 mmol/l |
Comment on the results of these blood tests and the possible causes of the man's weight gain and fatigue.
