Relevant investigations
| Test | Value |
| Hb | 101 g·L−1 |
| ESR | 135 mm·1st·h−1 |
| Urea | 15 mmol·L−1 |
| Creatinine | 167 mmol·L−1 |
| Total protein | 126 g·L−1 |
| Albumin | 26 g·L−1 |
| Ig electrophoresis | Polyclonal IgG |
| Angiotensin converting enzyme | Normal |
| Serum PTH | Normal |
| P a,O2 | 8.80 kPa |
| Urine for Bence-Jones proteins | Negative |
| Tuberculin test | Negative |
| Pleural fluid | |
| WBC | 467×106·L−1 (92% lymphocytes) |
| RBC | 6000×106·L−1 |
| Glucose | 4.9 mmol·L−1 |
| Protein | 73 g·L−1 |
| LDH | 370 IU·L−1 |
| Bone marrow aspirate and trephine biopsy | Negative for infection and malignancy |
| Rectal biopsy | Normal |
| Bone scan | Normal |
| Stains and cultures of sputa, bronchial wash and pleural fluid for bacteria, TB and fungi | Negative |
Hb: haemoglobin
ESR: erythrocyte sedimentation rate
Ig: immunoglobulin
PTH: parathyroid hormone
Pa,O2: oxygen tension in arterial blood
WBC: white blood cell count
RBC: red blood cell count
LDH: lactate dehydrogenase
TB: tuberculosis