| YLACO | Lacosamide (Vimpat), Serum | — |
| YLACTC | Lactic Acid, CSF | — |
| YLCTFL | Lactoferrin, Fecal | — |
| YLTT | Lactose Tolerance | Enzymatic Hexokinase Method |
| YLAMO | Lamotrigine (Lamictal) | — |
| YBFLD | LD, Body Fluid | Electrochemiluminescence Immunoassay |
| YLD | LDH | Electrochemiluminescence Immunoassay |
| YLDIS | LDH (Lactate Dehydrogenase) Isoenzymes | — |
| YCLD | LDH (Lactate Dehydrogenase) Total, CSF | Quantitative Enzymatic Assay |
| YLDLR | LDL Cholesterol (Direct) | — |
| YPBU | Lead, 24-Hour Urine | — |
| YLEDCAP | Lead, Capillary | — |
| YLEADBS | Lead, Filter Paper Blood Spot | — |
| YPBRU | Lead, Random Urine | — |
| YLEAD | Lead, Venous | — |
| YPBIEP | Lead, ZPP, Industrial Exposure Panel, Adult | — |
| YLEFLUM | Leflunomide Metabolite, Serum or Plasma | — |
| YLGCU | Legionella Culture | — |
| YLEGMA | Legionella pneumophila Antibodies (Types 1-6) IgG, IgM, IgA | — |
| YLEAG | Legionella pneumophila Antigen, Urine | — |
| YLEGDF | Legionella pneumophila DFA | — |
| YLSQPCR | Legionella Species by Qualitative PCR | — |
| YLEMON | Lemon IgE | — |
| YLENTIL | Lentil IgE | — |
| YLPTI | Leptin, Serum | — |
| YLEPA | Leptospira Antibody, IgM by Dot Blot | — |
| YLETTCE | Lettuce IgE | — |
| YLCMS | Leukemia/Lymphoma Immuno by Flow | — |
| YLTE4 | Leukotriene E4, 24 Hr., Urine | — |
| YLXPO | Lexapro (Escitalopram), Serum | — |
| YLBRM | Librium and Nordiazepam | — |
| YLPAS | Lipase | Colorimetric Enzymatic Method |
| YLIPEA | Lipid Panel, Extended (Non-HDL) | Quantitative Spectrophotometry / Quantitative Enzymatic Assay |
| YLIPM | Lipid Profile M | Please see individual components for methodology |
| YLIPD | Lipid Profile, Basic (Lipid Profile plus Glucose) | Please see individual components for methodology |
| YLIPOP | LipoFit by NMR, Particle Count Only | — |
| YLPPA | Lipoprotein (a) | — |
| YLI | Lithium | Colorimetric Method |
| YLCAT1 | Liver Cytosolic Antigen Type 1 (LC-1) Antibody, IgG | — |
| YFLFFTA | Liver Fibrosis Panel | — |
| YFIBROHV | Liver Fibrosis, Chronic Viral Hepatitis (FibroMeter) | — |
| YLIV2 | Liver Profile 2 (Liver Profile plus GGT) | Please see individual components for methodology |
| YLIVB | Liver Profile Basic | Please see individual components for methodology |
| YLKM1 | Liver-Kidney Microsome 1 Ab, IgG by ELISA | — |
| YLKMA | Liver-Kidney Microsome Antibody, IgG by IFA | — |
| YLOBSTR | Lobster IgE | — |
| YLORA | Lorazepam (Ativan) | — |
| YLPA2 | Lp-PLA2, Lipoprotein-Assoc. Phospholipase A2, Activity (PLAC) | — |
| YLRP4 | LRP4 Autoantibody Test | — |
| YLARP | Lupus Anticoagulant Reflex Panel | — |
| YLACCP | Lupus Anticoagulant/Cardiolipin ABS panel | LUPP-Instrumentation Laboratory ACL Top 750; ACABP-Multiplex Flow Immunoassay; BET2-Semi-Quantitative Enzyme-Linked Immunosorbent Assay |
| YLUPP | Lupus Panel | Instrumentation Laboratory ACL Top 750 |
| YLHS | Luteinizing Hormone | Electrochemiluminescence Immunoassay |
| YLYMCRPS | Lyme (Borrelia burgdorferi) Abs, Total, CSF | — |
| YWBLC | Lyme (Borrelia burgdorferi) IgG/IgM Western Blot CSF | — |
| YLNBAB | Lyme CNS IgG a/Ab Index Reflex | — |
| YLTAR | Lyme Dis Abs w/ref to W. Blot | — |
| YLYMPCR | Lyme Disease (Borrelia Species) by PCR, Blood | — |
| YBTICK | Lyme Disease (Borrelia Species) by PCR, Tick | — |
| YLDSS | Lyme Disease Serology, Serum | — |
| YPBORB | Lyme Disease, Molecular Detection, PCR, Blood | — |
| YLAMPP | Lymphocyte Antigen & Mitogen Proliferation Panel | — |
| YMITGEN | Lymphocyte Proliferation | Cell Culture |
| YLSP2 | Lymphocyte Subset Panel 2 - CD4 % and Absolute | — |
| YLSP5 | Lymphocyte Subset Panel 5 - Total Lymphocyte Enumeration | — |
| YLSP6 | Lymphocyte Subset Panel 6 - Total Lymphocyte Enumeration w/CD45RA & CD45RO | — |
| YLSNGS | Lynch Syndrome Panel, Sequencing and Deletion/Duplication | — |
| YLYSO | Lysozyme, Serum | — |
