The probable yield of routine investigations. Adapted from Warlow et al8
| Investigation | Estimated yield (%) |
| Full blood count | 1 |
| ESR/plasma viscosity | 2 |
| Urea and electrolytes | 3 |
| Plasma glucose | 5 |
| Plasma cholesterol | 45 |
| Urinalysis | 5 |
| ECG (12 lead) | 17 |
| Unenhanced CT brain scan | 20 |
ESR, erythrocyte sedimentation rate; ECG, electrocardiogram; CT computed tomography.