| MCR | Medical Corps Reserve; melanocortin receptor; message competition ratio; metabolic clearance rate; m... |
|---|---|
| MDTR | mean diameter-thickness ratio |
| M/E | myeloid/erythroid [ratio] |
| MER | mean ejection rate; medical emergency room; methanol extraction residue; murmur/energy ratio |
| M/F | male/female [ratio] |
| S/D | systolic-diastolic ratio |
|---|---|
| V.R. | variable ratio |
| VBR | ventricle brain ratio |
| W/D | wet-dry weight ratio |