| Abbreviation | Meaning |
|---|---|
| M | murmur (heart murmur or heart attack that can cause death) |
| MACE | Major adverse cardiovascular events |
| MAC | Mycobacterium avium complex |
| MAE | moves all extremities |
| MAHA | microangiopathic hemolytic anemia |
| MAL | midaxillary line |
| MALT | mucosa-associated lymphoid tissue |
| MANOS | minilaparoscopy assisted natural orifice surgery |
| MAOI | monoamine oxidase inhibitor |
| Mφ | macrophage |
| MAP | mean arterial pressure |
| MAR | Medication Administration Record |
| MARSA | methicillin- and aminoglycoside-resistant Staphylococcus aureus |
| MAS | Morgagni–Adams–Stokes syndrome meconium aspiration syndrome |
| MAST | Michigan alcohol screening test |
| MAT | multifocal atrial tachycardia microscopic agglutination test |
| MBSS | modified barium swallow study |
| MC | metacarpal bone |
| MCA | mucinous cystadenoma |
| MCAT | Medical College Admission Test |
| MCC | MotorCycle Collision, Motor Cycle Crash |
| MCD | minimal change diseaseharmful can cause cancer |
| MCDK | multicystic dysplastic kidney |
| MCP | metacarpophalangeal joint |
| MCHC | mean corpuscular hemoglobin concentration |
| MCH | mean cell hemoglobin; mean corpuscular hemoglobin |
| MC&S | microscopy, culture, and sensitivity (the investigation steps in processing microbiology samples) |
| MCTD | mixed connective tissue disease |
| MCV | mean corpuscular volume |
| MDCT | multidetector row computerized tomography |
| MDD | major depressive disorder |
| MDE | major depressive episode |
| MDI | metered dose inhaler |
| MDip | Master Diploma (specialization) |
| MDS | myelodysplastic syndrome |
| ME | UK: Myalgic Encephalopathy ( = Chronic Fatigue Syndrome or "CFS") |
| M/E | microscopic examination |
| MEC | Moderate emetic chemotherapy |
| MEDLINE | Medical Literature Analysis and Retrieval System Online (U.S. National Library of Medicine) |
| MELD | Model for End-Stage Liver Disease |
| MEN | multiple endocrine neoplasia |
| MeSH | Medical Subject Headings (U.S. National Library of Medicine) |
| MET | metabolic equivalent |
| met | metastasis (pronounced like the word met; plural mets) |
| MFM | maternal and fetal medicine |
| Mg | magnesium |
| MG | myasthenia gravis |
| MGN | membranous glomerulonephritis |
| MGPE | milligrams of phenytoin equivalents |
| MgSO4 | magnesium sulfate (Do not use this abbreviation. Write out the name. Per the do-not-use list.) |
| MGUS | monoclonal gammopathy of undetermined significance (unknown or uncertain may be substituted for undetermined) |
| MHA-TP | microhemagglutination assay for T. pallidum |
| MHMR | mental health and mental retardation |
| MHW | Mental Health Worker |
| MI | myocardial infarction |
| MIC | minimum inhibitory concentration |
| MICA | mental illness and chemical abuse; mentally ill chemical abuser |
| MICU | mobile intensive care unit / medical intensive care unit |
| MIF | Müllerian inhibitory factor |
| MIP | Maximum intensity projection, a technique used to enhance CT, MRI, MRA, and PET images |
| MIS | Minimally Invasive Surgery Müllerian Inhibiting Substance |
| MLC | mixed lymphocyte culture |
| MLE | midline episiotomy |
| MM | myeloid metaplasia middle meningeal multiple myeloma |
| M&M | morbidity and mortality |
| MMFR | midmaximal flow rate |
| MMI | maximum medical improvement |
| MMK | Marshall–Marchetti–Kranz procedure |
| MMM | moist mucus membranes Myelofibrosis with Myeloid Metaplasia |
| MMP | medical marijuana patient Medical Monitoring Project (of the US CDC) |
| MMPI | Minnesota Multiphasic Personality Inventory |
| MMR | measles, mumps, and rubella combined vaccination mismatch repair |
| MMR-D | mismatch repair deficiency syndrome |
| MMSE | mini-mental state examination |
| MMT | malignant mesenchymal tumor Mixed Mullerian Tumor |
| MN | membranous nephropathy |
| MND | motor neurone disease, also known as amyotrophic lateral sclerosis (ALS), Lou Gehrig's disease or Charcot disease |
| MOB | mother of baby |
| mod | moderate; modified |
| MODY | maturity onset diabetes of the young |
| Mo | monocytes |
| MoM | multiples of the median |
| MOM | milk of magnesia |
| Mono-Di | monochorionic-diamniotic twins |
| Mono-Mono | monochorionic-monoamniotic twins |
| MOPP | mechlorethamine, vincristine, procarbazine, and prednisone in combination (older treatment for Hodgkin's lymphoma) |
| MPA | medroxyprogesterone acetate |
| MPD | Main pancreatic duct |
| MPD(s) | myeloproliferative disease(s) |
| MPGN | membranoproliferative glomerulonephritis |
| MPO | myeloperoxidase |
| MPT | multi-professional team |
| MPV | mean platelet volume |
| MR | medical representative mental retardation mitral regurgitation modified release (compare time release technology (medicine)) menstrual regulation (unsafe abortion) |
| MRA | magnetic resonance angiography |
| MRCP | magnetic resonance cholangiopancreatography |
| MRG | murmurs, rubs, and gallops (see heart sounds) |
| MRI | magnetic resonance imaging |
| MRSA | methicillin-resistant Staphylococcus aureus |
| MS | medical student (MS-1, MS-2, MS-3, MS-4) mental status (see mental status examination) mitral stenosis multiple sclerosis |
| MS-AFP | maternal serum alpha-fetoprotein |
| MSD | musculoskeletal disorder |
| MSDU | medical surgical day unit |
| MSE | mental status examination |
| MSH | melanocyte-stimulating hormone |
| MSK | medullary sponge kidney musculoskeletal |
| MSM | men who have sex with men |
| MSMW | men who have sex with men and women |
| MSO4 | morphine sulfate (Do not use this abbreviation. Write out the name. Per the do-not-use list.) |
| MSOF | multisystem organ failure |
| MSSA | methicillin-sensitive Staphylococcus aureus (contrast with MRSA) |
| MSU | midstream urine sample (used in testing for presence of urinary tract infections) monosodium urate |
| MSUD | maple syrup urine disease |
| MT | metatarsal bone |
| MTBI | mild traumatic brain injury |
| MtF | Male to Female transgender person (trans woman) |
| MTP | metatarsalphalangeal |
| MTX | methotrexate |
| MUGA | Multiple gated acquisition scan |
| MUSE | medicated urethral system for erections |
| MVA | motor vehicle accident |
| MVC | motor vehicle crash |
| MVI | Multivitamin |
| MVo2 | mixed venous oxygen concentration |
| MVP | mitral valve prolapse |
| MVPS | mitral valve prolapse syndrome |
| MVR | mitral valve replacement |