| MFR | mean flow rate; mucus flow rate |
|---|---|
| MHR | major histocompatibility region; malignant hyperthermia resistance; maternal heart rate; maximal hea... |
| MMR | mass miniature radiography; masseter muscle rigidity; maternal mortality rate; measles-mumps-rubella... |
| PCR | patient contact record; phosphocreatinine; plasma clearance rate; polymerase chain reaction; post-co... |
| PFR | parotid flow rate; peak flow rate |