| RRR | regular rhythm and rate; renin release rate (or ratio) |
|---|---|
| SER | sebum excretion rate; sensitizer enhancement ratio; sensory evoked response; service; smooth endopla... |
| SR | sarcoplasmic reticulum; saturation recovery; scanning radiometer; screen; secretion rate; sedimentat... |
| TPR | temperature, pulse, and respiration; testosterone production rate; third party reimbursement; total ... |
| UFR | ultrafiltration rate; urine filtration rate |