| Phosphate | Phos | SST/Serum | 48 hours |
| Potassium | POT | SST/Serum | 48 hours |
| Progesterone | PROG | SST/Serum | 48 hours |
| Prolactin | PROL | SST/Serum | 48 hours |
| PSA (total) | TPSA | SST/Serum | 48 hours |
| Protein/Creatinine Ratio | PRCR | Urine | 48 hours |
| Prothrombin Time (PT) | PT | Citrate | 4 hours |