| Test name | Alternative name for |
|---|
| Occular Impression Cytology | Cytology - Conjuntival Impression |
| Occult Blood | |
| OCP | Ova, cysts and parasites |
| ODG 1p/19q LOH - Paraffin FISH | 1p/19q gene deletion in Oligodendrogliomas - Paraffin FISH |
| Oesophageal Fluid for Cytology | Cytology - Oesophageal, Bile Duct, Pancreatic & Ampulla Specimens |
| Oestradiol | |
| Oestradiol (LCMS) | |
| Oestradiol (Ultra-sensitive) | |
| Oestradiol LCMS | Oestradiol (Ultra-sensitive) |
| Oestriol Urine | |
| OJ antibodies | Anti Myositis antibodies |
| Olanzapine | |
| Oligoclonal IgG (CSF) | CSF Oligoclonal Bands |
| Opiate Confirmation | Urine Drug Screen Confirmations |
| Osmolality | |
| Osmolality Urine | |
| OSTASE | Bone Specific Alkaline Phosphatase Ostase |
| Osteocalcin | |
| Ova, cysts and parasites | |
| Ovarian autoantibodies | Anti Ovarian Antibodies |
| Overnight DST | Dexamethasone Suppression test |
| Oxalate | |
| Oxalate Urine | |
| Oxcarbazepine | Oxcarbazepine metabolite |
| Oxcarbazepine metabolite | |