| Abbreviations | Meaning |
 | IGFBP-5 | Insulin-like Growth Factor-binding Protein-5 |
 | IGP | Intestinal Glycoprotein |
 | ILDBP | Interleukin-dependent Deoxyribonucleic Acid-binding Protein |
 | IPA | Invasion Plasmid Antigens Proteins |
 | IPROCLASS | Integrated Protein Classification |
 | IRBP | Intestinal Retinol-binding Protein |
 | IREBP | Iron-responsive Element Binding Protein |
 | JIPID | Japan International Protein Information Center |
 | KIP | Key Intermediary Protein |
 | KP | Kaufmann-Peterson [base]; Keratitic Precipitate; Keratitis Punctata; Kidney Protein; Killed Parenteral [vaccine]; Klebsiella Pneumoniae |
 | KRP | Kolmer Test With Reiter Protein [antigen]; Krebs-Ringer Phosphate |
 | KSP | Karolinska Scales Of Personality; Kidney-specific Protein |
 | L-CAPS | Low-Density Lipoprotein Coronary Atherosclerosis Prospective Study |
 | LA-BP | Low Affinity Binding Protein |
 | LACI | Lacidipine; Lipoprotein-associated Coagulation Inhibitor |
 | LAMP | Limbic System-associated Membrane Protein; Lysosome-associated Membrane Protein |
 | LAP | Latency-associated Protein |
 | LAP | Leukemia-associated Phosphoprotein |
 | LAP | Liver-enriched Transcriptional Activator Protein |
 | LBP | Lipopolysaccharide-binding Protein; Local Binary Pattern; Low Back Pain; Low Blood Pressure; Lumbar Back Pain |
 | LCAS | Lipoprotein And Coronary Atherosclerosis Study |
 | LDL | Low Density Lipoprotein |
 | LDL | Loudness Discomfort Level; Low-density Lipoprotein |
 | LDL A | Low-density Lipoprotein Receptor Class A |
 | LDL B | Low-density Lipoprotein Receptor Class B |
 | LDL CHOLESTEROL | Low-density Lipoprotein Cholesterol |
 | LDL-C, LDL-C | Low-density Lipoprotein/cholesterol Complex |
 | LDL/HDL | Low-density Lipoproteins/high-density Lipoproteins Ratio |
 | LDLA | Low-density Lipoprotein Apheresis |
 | LDLP | Low-density Lipoprotein |
 | LDLR, LDL-R | Low-density Lipoprotein Receptor; Low-Density Lipoprotein Receptor Mutation Database |
 | LEP | Lipoprotein Electrophoresis |
 | LETS | Large External Transformation-sensitive [protein]; Leiden Thrombophilia Study |
 | LIV-BP | Leucine, Isoleucine, And Valine-binding Protein |
 | LL | Lipoprotein Lipase |
 | LMMG | Low Molecular Mass G [protein] |
 | LMWP | Low-molecular-weight Proteinuria |
 | LP | Labile Protein |
 | LP | Lipoprotein; Sound Pressure Level |
 | LP(A) | Lipoprotein A |
 | LPA | Latex Particle Agglutination; Left Pulmonary Artery; Lipoprotein A; Lysophosphatidic Acid |
 | LPB, LP(B) | Lipoprotein B |
 | LPD | Lovelace Patient Database; Low-protein Diet; Luteal Phase Defect; Lymphoproliferative Disease |
 | LPDF | Lipoprotein-deficient Fraction |
 | LPE | Lipoprotein Electrophoresis; Liquid Phase Epitaxy; Lysophosphatidylethanolamine |
 | LPI | Left Posterior-inferior; Lysinuric Protein Intolerance |
 | LPL | Lipoprotein Lipase |
 | LPL | Lethal-potentially-lethal; Lichen Planus-like Lesion; Lipoprotein Lipase; Local Probability Of Lesion |
 | LPLA | Lipoprotein Lipase Activity |
 | LPX, LP-X | Lipoprotein-X |