| NMDA | N-methyl-D-Aspartate Receptor Antibody, IgG | — |
| NMTHUR | N-Methylhistamine, 24-Hour Urine | — |
| NMTHR | N-Methylhistamine, Random Urine | — |
| NTXU | N-Telopeptide Cross Linked (NTx) Random or 24 Hr. Urine | — |
| SNTP | N-Telopeptide, Cross-Linked, Serum | — |
| CGMGN | N. Gonorrhoeae, Chlamydia & Mycoplasma Genitalium NAAT | Nucleic Acid Amplification Testing |
| GCCMGN | N. Gonorrhoeae, Chlamydia, Trichomonas & Mycoplasma Genitalium NAAT | Nucleic Acid Amplification Testing |
| IFBETA | NAbFeron Neutralizing Antibody | — |
| NRCY | Narcolepsy Evaluation, HLA DQ6 by DNA | — |
| NSFIB | NASH FibroTest | — |
| YNKNKT | Natural Killer Cell and Natural Killer T-Cell Panel | Semi-Quantitative Flow Cytometry |
| NKCE | Natural Killer Cells Enumeration | — |
| NAVYBN | Navy Bean IgE | — |
| MNVR | Neisseria meningitidis (Meningococcal) IgG Vaccine Response | — |
| NPTRN | Neopterin, Serum | — |
| NETTLE | Nettle Weed IgE | — |
| NF1Z | Neurofibromatosis Type 1, NF1, Full Gene Analysis | — |
| NFLC | Neurofilament Light Chain, Plasma | — |
| NMOGA | Neuromyelitis Optica (NMO)/Aquaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Assay, Serum | — |
| NSES | Neuron Specific Enolase (NSE) | — |
| ANNA | Neuronal Abs (Hu, Ri, Yo, Tr/DNER), IgG | Qualitative Immunoblot / Semi-Quantitative Indirect Fluorescent Antibody (IFA) |
| NAAB | Neutrophil Associated Antibodies | — |
| NOBA | Neutrophil Oxidative Burst Assay (DHR) | — |
| NGSHM | NGS for Myeloid Neoplasms | — |
| NCKL | Nickel, Serum | — |
| NICTN | Nicotine & Metabolites, Serum | — |
| NICU | Nicotine Metabolite, Urine | — |
| LIPOPR | NMR Lipoprofile | — |
| NOCCU | Nocardia Culture | — |
| NCASAB | Non-Criteria APS Syndrome (aPs, aPt, aPs/aPt) AB Panel | — |
| NORT | Nortriptyline | — |
| NVDET | Norwalk Virus Detection (Norovirus) | — |
| NPM1 | NPM1 Mutation Detection | — |
| PBNP | NT-proBNP | — |
