| YMACNUT | Macadamia Nut, IgE | — |
| YMACKRL | Mackerel IgE | — |
| YMCRAD | Macroamylase Determination | — |
| YMPRL | Macroprolactin | — |
| YMG | Magnesium | Colorimetric Method |
| YMGF | Magnesium, Fecal | — |
| YMRBC | Magnesium, RBC | — |
| YUMGB | Magnesium, Urine, 24 Hour | — |
| YUMGS | Magnesium, Urine, Random | — |
| YPSPCR | Malaria (Plasmodium Species) by PCR | — |
| YMHPS | Malignant Hyperthermia Panel, Sequencing | — |
| YMNB | Manganese, Blood | Triple-Quadrupole Inductively Coupled Plasma-Mass Spectrometry (ICP-MS/MS) |
| YMAN | Manganese, Serum | Quantitative Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) |
| YWBM | Manganese, Whole Blood | Quantitative Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) |
| YMANGO | Mango IgE | — |
| YMBLS | Mannose Binding Lectin | — |
| YFBN1 | Marfan Syndrome, FBN1 Sequencing | — |
| YMSSI1 | Maternal Serum Screening, Integr Spec #1 PAPP-A, NT | — |
| YMSSI2 | Maternal Serum Screening, Integrated Spec #2 | — |
| YMMP9A | Matrix Metalloproteinase-9 (MMP-9) | Enzyme-Linked Immunosorbent Assay (ELISA) |
| YRUOL | Measles (Rubeola) Antibody, IgG | — |
| YMEAM | Measles (Rubeola) Antibody, IgM | — |
| YMVNAAT | Measles Virus by Qualitative NAAT | — |
| YMEASLE | Measles Virus PCR (Swab or Urine) | — |
| YMMRRPS | Measles/Mumps/Rubella Immunity, Qualitative | — |
| YMMRVI | Measles/Mumps/Rubella/Varicella Zoster Immunity Qualitative | — |
| YMMRVPAN | Measles/Mumps/Rubella/VZV Quant Antibody Assessment Panel, IgG | — |
| YMDS11 | Meconium Drug Screen Panel 11 | — |
| YMDSPR | Meconium Drug Screen Panel 12 w/Alcohol | — |
| YMSHA | Melanocyte Stimulation Hormone, Alpha (a-MSH) | — |
| YMLTNP | Melatonin, Serum or Plasma | — |
| YMEEP | Meningitis/Encephalitis Panel | — |
| YFMEP | Meperidine (Demerol) and Normeperidine, Serum | — |
| YCDMEPE | Meperidine & Metabolite, UR, Quant | — |
| YMPDN | Meperidine and Metabolite, Serum | — |
| YMEPURQ | Meperidine, Urine w/reflex to Quantitation | — |
| YHG | Mercury, Blood | — |
| YURHG | Mercury, Random or 24 Hour Urine | — |
| YMETN | Metanephrines Urine Total/Fractionated Random or 24 Hr. | — |
| YMFPF | Metanephrines, Fractionated, Plasma Free | — |
| YMTFRM | Metformin | — |
| YMETHM | Methadone & Metabolite, Urine Quantitation | — |
| YMCUN | Methadone Screen & Confirmation, Urine | — |
| YMETHS | Methadone, Serum/Plasma | — |
| YMETHME | Methamphetamine and Metabolite, Blood | — |
| YMEOH | Methanol, Blood | — |
| YMHGV | Methemoglobin | — |
| YMETX | Methotrexate | — |
| YNMES | Methsuximide (Celontin) | — |
| YMMASR | Methylmalonic Acid (MMA) Serum Quantitative | — |
| YMMMAL | Methylmalonic Acid (MMA) Urine Quantitative | — |
| YALBM | Microalbumin, Random Urine | Immunoturbidimetric Assay |
| YMCRT | Microalbumin/Creatinine Ratio, 24 Hour Timed Urine | Immunoturbidimetric Assay |
| YMCRR | Microalbumin/Creatinine Ratio, Urine | Immunoturbidimetric Assay |
| YMICSPOR | Microsporidia by PCR | — |
| YMILK | Milk IgE | — |
| YAMIT | Mitochondrial (M2) Antibody, IgG | Semi-Quantitative Enzyme-Linked Immunosorbent Assay (ELISA) |
| YMTDNA | Mitochondrial Disorders Panel (mtDNA & Nuclear Genes) | — |
| YMITOSP | Mitotane, Serum or Plasma | — |
| YMOLYBD | Molybdenum Quant, Serum or Plasma | — |
| YQMPSS | Monoclonal Gammopathy | — |
| YMPSU | Monoclonal Protein Study, 24 Hr. Urine | — |
| YMONX | Mononucleosis | Direct Solid-Phase Immunoassay |
| YMORPU | Morphine Level, Urine | — |
| YFMNPP | Motor Neuropathy Panel | — |
| YMSNER | Motor Sensory Eval | — |
| YMDS2 | Movement Disorder, Autoimmune Eval, Serum | — |
| YMPLMUT | MPL Mutation Detection | — |
| YMRSANS | MRSA by PCR, Nasal | — |
| YMRSCU | MRSA Culture | — |
| YMTHFN | MTHFR DNA Analysis | Polymerase Chain Reaction (PCR) / Fluorescence Monitoring |
| YMUGWRT | Mugwort IgE | — |
| YMEN1 | Multiple Endocrine Neoplasia Type 1 (MEN1) Sequencing | — |
| YMSPL | Multiple Sclerosis Panel | — |
| YMUMPG | Mumps Ab IgG | — |
| YMUMPQT | Mumps IgG, Quantitative | — |
| YMUMPM | Mumps IgM Abs | — |
| YMUMPCR | Mumps Virus by PCR | — |
| YMUSHRM | Mushroom IgE | — |
| YMUSK | MuSK Antibody | — |
| YMUSTRD | Mustard IgE | — |
| YFMGRP | Myasthenia Gravis Reflex Panel | — |
| YTBAPR | Mycobacterium tuberculosis Amplified Direct Detection | — |
| YMYPH | Mycophenolic Acid (Cellcept) | — |
| YMYCOPC | Mycoplasma & Ureaplasma Species (Urogenital) by PCR | — |
| YMGEN | Mycoplasma genitalium rRNA | Transcription-Mediated Amplification |
| YAMGEN | Mycoplasma genitalium, Transcription-Mediated Amplification, Urine or Urogenital Swab | Transcription-Mediated Amplification, and Dual Kinetic Assay |
| YMYAGM | Mycoplasma pneumoniae Antibodies, IgG & IgM | — |
| YMYABG | Mycoplasma pneumoniae Antibody, IgG | — |
| YMYPM | Mycoplasma pneumoniae Antibody, IgM | — |
| YMYCPNA | Mycoplasma Pneumoniae by PCR | — |
| YMYD88 | MYD88 Mutation Detection, Peripheral blood | — |
| YMAGAB | Myelin Associated Glycoprotein (MAG) Antibody, IgM | — |
| YMYBP | Myelin Basic Protein | — |
| YMOGAG | Myelin Oligodendrocyte Glycoprotein (MOG) Ab, IgG w/reflex | — |
| YMOGFS | Myelin Oligodendrocyte Glycoprotein IgG (FACS) Assay, Serum | — |
| YMYMPB | Myeloid Mutation Panel, Blood | — |
| YMYELOB | Myeloma Screening Panel | — |
| YMAS1 | Myelopathy, Autoimmune/Paraneoplastic Eval, Serum | — |
| YMPO | Myeloperoxidase (MPO) Antibody | — |
| YMPNPB | Myeloproliferative Neoplasm (MPN) Panel/Peripheral Blood | — |
| YMYOAST | Myocardial Antibody Screen w/reflex to Titer | — |
| YMYOGS | Myoglobin | — |
| YUMYG | Myoglobin, Urine | — |
| YFMYO3 | MyoMarker 3 Profile | — |
