| Macroprolactin |
| Magnesium |
| Malaria parasite |
| MCV |
| MCV Ab |
| Measles Ab (IgG) |
| Measles Ab (IgM) |
| Measles PCR |
| Mercury (Hg) |
| Metanephrines |
| Mono test |
| Morphine |
| MPO Ab |
| MSUD (DNPH) |
| MTHFR A 1298 C mutation |
| MTHFR C 677 T mutation |
| MTX |
| Mucopolysaccharides (MPS) |
| Mumps Ab (IgG) |
| Mumps Ab (IgM) |
| Mumps PCR |
| Mycobacterium Ab (IgA) |
| Mycobacterium Ab (IgG) |
| Mycobacterium Ab (IgM) |
| Mycobacterium Culture |
| Mycobacterium Direct smear |
| Mycobacterium PCR |
| Mycoplasma hominis culture |
| Mycoplasma Pneumonia Ab(IgG) |
| Mycoplasma Pneumonia Ab (IgM) |
| Mycoplasma Pneumonia PCR |
| Myoglobin |
| Maprotiline (drug abuse) |
| Mefenamic acid (drug abuse) |
| Meprobamates (drug abuse) |
| Mercury (drug abuse) |
| Metformin (drug abuse) |
| Meth amphetamines(drug abuse) |
| Methadone (drug abuse) |
| Methanol (drug abuse) |
| Metoclopramide (drug abuse) |
| Metoral (drug abuse) |
| Moclobemide (drug abuse) |
| Mono oxid carbon (Co)(drug abuse) |
| Morphine (drug abuse) |
