| Test | Specimen Requirements |
| Red Cell Count | 4mL EDTA (purple) |
| Red Cell Morphology (Urine) | Mid Stream Urine collection. Must be fresh. Call Lab courier for urgent pickup. |
| Red Cell Phenotyping for Rhesus antigens Other blood group antigens | 10 mL PLAIN (red) 10 mL PLAIN (red) |
| Reducing Substances Faeces | 20g Faeces. Must be fresh. |
| Renin* | 2 x 4 mL EDTA (purple). Separate plasma and freeze immediately. |
| Reticulin Antibody (Coeliac)* | 5-10 mL GEL (white / yellow) |
| Reticulin Stain | Bone Marrow Trephine |
| Reticulocytes | 4mL EDTA (purple) |
| Retinol (Vitamin A)* | 10ml GEL (white / yellow) or 10ml LITHIUM HEPARIN (green). Spin and freeze. |
| Rheumatoid Arthritis (RA) Factor | 10 mL GEL (white / yellow) |
| Riboflavin (Vitamin B2)* | 10 mL LITHIUM HEPARIN (green). Wrap in foil. |
| Rickettsia Serology Weil-Felix Screen | 10 mL GEL (white / yellow) |
| Rivotril (Clonazepam)* | 10 mL GEL (white / yellow) |
| Rohypnol (Flunitrazepam)* | 50 mL Random Urine |
| Rotavirus Antigen | Fresh faecal sample. |
| RPR (VDRL) Includes titre if positive | 10 mL GEL (white / yellow) |
| Rubella Antibodies IgG Antibody IgM Antibody | 10 mL GEL (white / yellow) 10 mL GEL (white / yellow) |