Occult Blood, faeces
Oestradiol (E2) *
Oestriol
OGTT
OJ antibodies
OKT3 Antibodies
Oligoclonal bands
Opiate screen - urine
Oral Dexamethasone suppression test
Oral Glucose Tolerance Test
Oral Glucose Tolerance test in Pregnancy
Orgaran - anti Xa
Osmo
Osmolality - 24 Hour urine
Osmolality - serum *
Osmolality - spot urine *
O. tsutsugamushi Serology
Ova, cysts and parasites
Ovarian Antibodies
Oxalate - urine
Oxazepam
Oxcarbazepine
Oxygen Saturation of Haemoglobin
Oxypurinol