| MER | mean ejection rate; medical emergency room; methanol extraction residue; murmur/energy ratio |
|---|---|
| O2ER | oxygen extraction ratio |
| AR | absolute risk; accounts receivable; achievement ratio; actinic reticuloid [syndrome]; active resista... |
| L/S | lactase/sucrase [ratio]; lecithin/ sphingomyelin [ratio]; lipid/saccharide [ratio]; longitudinal sec... |
| ECCE | Extra-Capsular Cataract Extraction |