| Selenium |
| Serum protein immunoelectrophoresis |
| Sugar chromatography |
| Sodium |
| Special stain |
| Sputum culture |
| Stone analysis |
| Stool Culture |
| Stool Exam (1) |
| Stool fat |
| Sucrose hemolysis test |
| Stool Exam (2) |
| Stool Exam (3) |
| Sickle prep |
| Scabiasis |
| Scatch test |
| Semen analysis |
| Semen culture |
| Semen fructose |
| SGOT (AST) |
| SGPT (ALT) |
| SHBG |
| Specific IgE (Food allergens) |
| Specific IgE (Respiratory allergens) |
| Selenium |
| Sweat test |
| Synovial fluid culture |
| Strongyloides stercoralis Ab |
| Specific IgE (Mix allergens) |
| Serum Osmolality |
