Table 1. Frequently ordered investigations in the open group (>20%).
Values are n (%).
| Laboratory investigations | |
| Complete blood count | 337 (90.35) |
| Erythrocyte sedimentation rate | 322 (86.33) |
| Serum electrolytes | 319 (85.52) |
| Syphilis serology | 308 (82.57) |
| C-reactive protein | 305 (81.77) |
| Angiotensin converting enzyme | 286 (76.68) |
| Electrophoresis of serum proteins | 254 (68.10) |
| Serum calcium | 250 (67.02) |
| Tuberculin skin test | 240 (64.34) |
| Hepatic tests | 200 (53.62) |
| Antinuclear antibodies | 159 (42.63) |
| IGRA | 152 (40.48) |
| HLA B27 | 143 (38.34) |
| Lysozyme | 137 (36.73) |
| Lyme disease serology | 132 (35.39) |
| HLA determination | 113 (30.29) |
| Hepatitis C serology | 105 (28.15) |
| Antineutrophil cytoplamic antibodies | 102 (27.35) |
| Rheumatoid factor | 100 (26.81) |
| Hepatitis B serology | 99 (26.54) |
| Herpes simplex virus 1 and 2 serology | 93 (24.93) |
| Creatinine | 93 (24.93) |
| Radiological procedures | |
| Chest CT | 174 (46.65) |
| Chest X-ray | 156 (41.82) |
| Brain MRI | 80 (21.45) |