| Term | Definition / Meaning / Stand for |
| MDMA |
3,4-Methylenedioxymethamphetamine |
| MAC |
Macrophage Activation Complex |
| MRE |
Magnetic Resonance Elastometry |
| MRE |
Magnetic Resonance Encephalography |
| MRP |
Major Regulatory Protein |
| MCL |
Malignant Cutaneous Lymphoma |
| MDS |
Malignant Disease States |
| MDS |
Malignant Diseases and Syndromes |
| MHS |
Malignant Hyperthermia Syndrome |
| MPR |
Malignant Pleural Retraction |
| MDA |
Malondialdehyde |
| MMP-2 |
Matrix Metalloproteinase-2 |
| MMP-9 |
Matrix Metalloproteinase-9 |
| MPR |
Maximal Physiological Response |
| MAD |
Maximum Admissible Dose |
| MIP |
Maximum Inspiratory Pressure |
| MNS |
Maximum Normal Systolic Pressure |
| MGG |
May-Grunwald Giemsa Staining |
| MAP |
Mean Arterial Pressure |
| MTS |
Mean Transit Study |
| MSL |
Medial Saphenous Ligament |
| MEP |
Median Effective Pressure |
| MCR |
Medical Case Report |
| MGT |
Medical Genetic Testing |
| MHT |
Medical Hormonal Therapy |
| MPT |
Medical Proficiency Test |
| MTE |
Medical Treatment Effectiveness |
| MNB |
Medullary Nephrosclerosis Block |
| MDA5 |
Melanoma Differentiation-Associated Protein 5 |
| MTA |
Meningothelial Tumor of the Adrenal Gland |
| MAT |
Metabolic Acidosis Therapy |
| MRA |
Metabolic Rate of Activity |
| MIBG |
Metaiodobenzylguanidine Scintigraphy |
| MTT |
Methotrexate |
| MTHFR |
Methylenetetrahydrofolate Reductase |
| MGC |
Methylglyoxal Clearance |
| MDP |
Methylprednisolone |
| MAD |
Microbiological Analytical Detection |
| MCS |
Microcirculatory Studies |
| MCA |
Middle Cerebral Artery |
| MBD |
Mineral Bone Disease |
| MMP |
Mitochondrial Membrane Potential |
| MTT |
Mitochondrial Tension Testing |
| MTR |
Mitochondrial Thymidine Ratio |
| MTR |
Mitochondrial Translation Readthrough |
| MTP |
Mitochondrial Transmembrane Potential |
| MTT |
Mitotic Time Test |
| MTL |
Mitral Leaflet |
| MMT |
Modified Meningeal Test |
| MBE |
Molecular Bioengineering |
| MRG |
Molecular Regulation Gene |
| MAO |
Monoamine Oxidase |
| MDM |
Mucopolysaccharidosis Disorders of Metabolism |
| MPR |
Mucopolysaccharidosis Reconstruction |
| MPSI |
Mucopolysaccharidosis Type I |
| MPS |
Mucopolysaccharidosis |
| MMR |
Mucosal Membrane Reaction |
| MBL |
Mucous Bronchial Lavage |
| MGR |
Mucous Gelatinous Region |
| MRP |
Multidrug Resistance Protein |
| MDS |
Multiple Dissecting Syndromes |
| MAD |
Mutant Allele Detection |
| MRA |
Myelin-Associated Glycoprotein |
| MDS |
Myelodysplastic Syndromes |
| MIBI |
Myocardial Imaging with Ischemic Scintigraphy |
| MFM |
Myofibrillar Myopathy |
| MLT |
Myotonic Laryngeal Toxin |
| MRA |
Magnetic Resonance Angiography |
| MRE |
Magnetic Resonance Elastography |
| MRI |
Magnetic Resonance Imaging |