| MCID | minimum clinically important difference |
|---|---|
| MCM | methylmalonic coenzyme A mutase; minimum capacitation medium |
| MD | Doctor of Medicine [Lat. Medicinae Doctor]; magnesium deficiency; main duct; maintenance dose; major... |
| MDC | major diagnostic categories; Metoprolol in Dilated Cardiomyography [trial]; minimum detectable conce... |
| MDQ | memory deviation quotient; Menstrual Distress Questionnaire; minimum detectable quantity |