| Potassium | Stool | Chemistry - non-challenge | LP386620-1 | 1 |
| Prealbumin | Serum or Plasma | Chemistry - non-challenge | LP384496-8 | 1 |
| Pregnenolone | LP15817-7 | 1 |
| Pregnenolone | Serum or Plasma | Chemistry - non-challenge | LP381086-0 | 1 |
| Prekeratocytes | LP65312-8 | 1 |
| Prekeratocytes | Blood | Hematology and Cell counts | LP393418-1 | 1 |
| Pro prostate specific Ag isoform 2 | LP422240-4 | 1 |
| Pro prostate specific Ag isoform 2 | Serum or Plasma | Chemistry - non-challenge | LP427416-5 | 1 |
| Procainamide | Serum or Plasma | Drug toxicology | LP389207-4 | 1 |
| Proinsulin | LP14637-0 | 1 |
| Proinsulin | Serum or Plasma | Chemistry - non-challenge | LP381343-5 | 1 |
| Projected heparin concentration to reach target ACT | LP206571-4 | 1 |
| Projected heparin concentration to reach target ACT | Blood | Coagulation | LP393942-0 | 1 |
| Proline | Amniotic fluid | Chemistry - non-challenge | LP384268-1 | 1 |
| Proline | Cerebral spinal fluid | Chemistry - non-challenge | LP384271-5 | 1 |
| Proline | Serum or Plasma | Chemistry - non-challenge | LP384272-3 | 1 |
| Propionylcarnitine (C3) | Serum or Plasma | Chemistry - non-challenge | LP381585-1 | 1 |
| Propionylcarnitine (C3)+Palmitoylcarnitine (C16) | LP183637-0 | 1 |
| Propionylcarnitine (C3)+Palmitoylcarnitine (C16) | DBS | Chemistry - non-challenge | LP381999-4 | 1 |
| Propionylglycine | LP14518-2 | 1 |
| Propionylglycine | Urine | Chemistry - non-challenge | LP384287-1 | 1 |
| Prostaglandin F | LP15825-0 | 1 |
| Prostaglandin F2 | LP15826-8 | 1 |
| Prostaglandin F2 alpha | LP18191-4 | 1 |
| Prostaglandin F2 alpha | Urine | Chemistry - non-challenge | LP386402-4 | 1 |
| Prostaglandins | LP19203-6 | 1 |
| Prostate health index | LP423001-9 | 1 |
| Prostate health index | Serum or Plasma | Chemistry - non-challenge | LP427417-3 | 1 |
| Prostate specific Ag.protein bound | LP30916-8 | 1 |
| Prostate specific Ag.protein bound | Serum or Plasma | Chemistry - non-challenge | LP386151-7 | 1 |
| Protein | Body fluid | Chemistry - non-challenge | LP384456-2 | 1 |
| Protein | Cerebral spinal fluid | Chemistry - non-challenge | LP384457-0 | 1 |
| Protein | Dialysis fluid | Chemistry - non-challenge | LP384458-8 | 1 |
| Protein | Dialysis fluid peritoneal | Chemistry - non-challenge | LP384459-6 | 1 |
| Protein | Lower respiratory specimen | Chemistry - non-challenge | LP384465-3 | 1 |
| Protein | Serum or Plasma | Chemistry - non-challenge | LP384468-7 | 1 |
| Protein | Synovial fluid | Chemistry - non-challenge | LP384470-3 | 1 |
| Protein catabolic rate | LP411545-9 | 1 |
| Protein catabolic rate | Urine | Chemistry - non-challenge | LP448382-4 | 1 |
| Protein Fractions | Cerebral spinal fluid | Chemistry - non-challenge | LP384936-3 | 1 |
| Protein Fractions | Serum or Plasma | Chemistry - non-challenge | LP384937-1 | 1 |
| Protein fractions.oligoclonal bands.IgG | LP96204-0 | 1 |
| Protein fractions.oligoclonal bands.IgG | Cerebral spinal fluid | Chemistry - non-challenge | LP384945-4 | 1 |
| Protein S Free | LP28872-7 | 1 |
| Protein S Free | Platelet poor plasma | Coagulation | LP394130-1 | 1 |
| Protein.monoclonal band 1 | LP66338-2 | 1 |
| Protein.monoclonal band 1 | Serum or Plasma | Chemistry - non-challenge | LP384957-9 | 1 |
| Protein.monoclonal band 2 | LP33260-8 | 1 |
| Protein.monoclonal band 2 | Serum or Plasma | Chemistry - non-challenge | LP384959-5 | 1 |
| Protein.monoclonal isotype | Serum or Plasma | Chemistry - non-challenge | LP384973-6 | 1 |
| Prothrombin | LP16010-8 | 1 |
| Prothrombin activity | LP16011-6 | 1 |
| Prothrombin activity | Platelet poor plasma | Coagulation | LP394418-0 | 1 |
| Protoporphyrin | Serum or Plasma | Chemistry - non-challenge | LP386508-8 | 1 |
| Pseudouridine | Cerebral spinal fluid | Chemistry - non-challenge | LP383539-6 | 1 |
| Pseudouridine | Serum or Plasma | Chemistry - non-challenge | LP383540-4 | 1 |
| Pyknosis | LP30811-1 | 1 |
| Pyknosis | Blood | Hematology and Cell counts | LP393419-9 | 1 |
| Pyridinoline | LP14914-3 | 1 |
| Pyridinoline | Urine | Chemistry - non-challenge | LP384289-7 | 1 |
| Pyridoxal | Cerebral spinal fluid | Chemistry - non-challenge | LP385161-7 | 1 |
| Pyridoxal phosphate | Cerebral spinal fluid | Chemistry - non-challenge | LP385164-1 | 1 |
| Pyridoxine | Cerebral spinal fluid | Chemistry - non-challenge | LP385167-4 | 1 |
| Pyruvate | Blood | Chemistry - non-challenge | LP385603-8 | 1 |
| Pyruvate | Serum or Plasma | Chemistry - non-challenge | LP385607-9 | 1 |
| Pyruvate | Urine | Chemistry - non-challenge | LP385608-7 | 1 |
| Pyruvate kinase | LP15160-2 | 1 |
| Pyruvate kinase | Red Blood Cells | Chemistry - non-challenge | LP383223-7 | 1 |
| R-beta aminoisobutyrate | Cerebral spinal fluid | Chemistry - non-challenge | LP383764-0 | 1 |
| R-beta aminoisobutyrate | Serum or Plasma | Chemistry - non-challenge | LP383765-7 | 1 |
| RBC Dual Population | LP14575-2 | 1 |
| RBC Dual Population | Blood | Hematology and Cell counts | LP393433-0 | 1 |
| Rearrangements | LP7825-5 | 1 |
| Resistin | LP185757-4 | 1 |
| Resistin | Serum or Plasma | Chemistry - non-challenge | LP381327-8 | 1 |
| Respiratory - upper and lower - drugs | LP31443-2 | 1 |
| Reticulocyte corpuscular hemoglobin concentration mean | LP183488-8 | 1 |
| Reticulocyte corpuscular hemoglobin concentration mean | Blood | Hematology and Cell counts | LP393369-6 | 1 |
| Reticulocyte mean volume | LP62885-6 | 1 |
| Reticulocyte mean volume | Reticulocytes | Hematology and Cell counts | LP393365-4 | 1 |
| Retinol | LP15274-1 | 1 |
| Retinol | Serum or Plasma | Chemistry - non-challenge | LP385105-4 | 1 |
| Retinyl palmitate | LP34632-7 | 1 |
| Retinyl palmitate | Serum or Plasma | Chemistry - non-challenge | LP385112-0 | 1 |
| Rh | LP14541-4 | 1 |
| Rh | Blood | Blood bank | LP398719-7 | 1 |
| Rh group | LP17805-0 | 1 |
| Rh immune globulin screen | LP32837-4 | 1 |
| Rh immune globulin screen | Blood | Blood bank | LP399128-0 | 1 |
| Rheumatoid arthritis disease activity score | LP185753-3 | 1 |
| Rheumatoid arthritis disease activity score | Serum or Plasma | Chemistry - non-challenge | LP385476-9 | 1 |
| Rheumatoid arthritis disease activity score confidence interval | LP185755-8 | 1 |
| Rheumatoid arthritis disease activity score confidence interval | Serum or Plasma | Chemistry - non-challenge | LP385478-5 | 1 |
| Rheumatoid arthritis disease activity score level | LP185754-1 | 1 |
| Rheumatoid arthritis disease activity score level | Serum or Plasma | Chemistry - non-challenge | LP385477-7 | 1 |
| Rheumatoid factor | Serum or Plasma | Serology - non-micro | LP403920-4 | 1 |
| Riboflavin | Blood | Chemistry - non-challenge | LP385151-8 | 1 |
| Riboflavin | Serum or Plasma | Chemistry - non-challenge | LP385152-6 | 1 |
| Rotavirus | LP14844-2 | 1 |
| Rotavirus | Stool | Microbiology | LP378975-9 | 1 |