| PSU | photosynthetic unit; primary sampling unit |
|---|---|
| PU | palindromic unit; passed urine; pepsin unit; peptic ulcer; pregnancy urine; 6-propyluracil; prostati... |
| RTU | real-time ultrasonography; relative time unit; renal transplantation unit |
| SCU | self-care unit; special care unit |
| SDU | standard deviation unit; step-down unit |
| focus-forming unit | A measurement of the concentration of live virus in a given amount of fluid. This is measured by spreading a known amount of the fluid over a layer of cultured cells which are infected by the virus, then counting the number of areas in the culture which look infected. (09 Oct 1997) |
|---|---|
| laminar air flow unit | An air-filtering system used at some transplant facilities to remove particulate matter and fungi from the air. (16 Dec 1997) |
| lung unit | A respiratory bronchiole together with the alveolar ducts and sacs and pulmonary alveoli into which the respiratory bronchiole leads, considered by some to include the terminal bronchiole and its subdivisions, and called a pulmonary acinus. (05 Mar 2000) |