| H-ARS | Hematopoietic ARS (Radiation) |
| HA | High Alpha (olefin) |
| HA | Hem Agglutinin |
| HA | Hyaluronic Acid |
| HA Ortho | Hydroxy Apatite |
| HAART | Highly Active Anti Retroviral Therapy (AIDS) |
| HABP | hospital-acquired bacterial pneumonia |
| HACT | High Affinity Choline Transporter |
| HAE | Hereditary Angio Edema |
| HAI | Healthcare-Associated Infections |
| HAL | Hexyl Amino Levulinate |
| HALS | Hindered Amine Light Stabilizer |
| HAMA | Human Anti Murine Antibodies |
| HAP | Hazardous Air Pollutant |
| HAP | Hydroxy APatite |
| HAP | Hospital Acquired Pneumonia |
| HAPPE | Hydroxy Apatite Porous Poly Etheretherketone |
| HARS | HIV- Associated Adipose Redistribution Syndrome |
| HASE | Hydrophobically Alkali Soluble Emulsion |
| HATCP | Hydroxy Apatite Tri Calcium Phosphate (Orthopaedics) |
| HBCD | Hexa Br Cyclo Dodecane |
| HBCU | Historically Black College & University (USA) |
| HBGF | Heparin Binding Growth Factor |
| HBGFPP | Heparin Binding Growth Factor Protector & Promoter |
| HBIW | Hexa Benzyl hexaaza Iso Wurtzitane |
| HBM | High Bandwidth Memory |
| HBNP | Human B-type Natriuretic Peptide |
| HBO | Hyper Baric Oxygen |
| HBOC | Hemoglobin Based Oxygen Carrier |
| HBP | Heparin Binding Protein |
| HBS | 4-Hydroxy Benzene Sulfonate |
| HBSAG | Hepatitis B Surface Anti Gen |
| HBT | Heterojunction Bipolar Transistors |
| HBTU | 2-(1H-Benzotriazo 1-1-yl)-1,1,3,3 Tetramethyl Uronium hexafluorophosphate |
| HBV | Hepatitis B Virus |
| HC | Hydro Carbon |
| HC/BTLP | Human Cardiac / Brain Tolloid-Like Protein |
| HCBD | Hexa Chloro Buta Diene |
| HCC | Hydro Chloro Carbon |
| HCC | Hepato Cellular Carcinoma |
| HCFC | Hydro Chloro Fluoro Carbon |
| HCFC | Hydro Chloro Fluoro Carbon |
| HCG | Human Chorionic Gonadotropin |
| HCM | Hyper Calcemia of Malignancy |
| HCM Cardio | Hypertrophic CardioMyopathy |
| HCMV | Human Cyto Megalo Virus |
| HCR | Human Cytopathic Rotavirus |
| HCRF | Human Corticotropin Release Factor |
| HCT | Hydro Chloro Thiazide (DiUretics) |
| HCV | Hepatitis C Virus |
| HD | High Definition |
| HD Nephro. | Hemo Dialysis |
| HD Neuro. | Huntingtons Disease |
| HDAC | Histone De ACetylase |
| HDCO | Hydroxy Didehydro Caroten One |
| HDDA | Hexane Diol Di Acrylate |
| HDDVE | Hexane Diol Di Vinyl Ether |
| HDE | Humanitarian Device Exemption |
| HDF | HemoDiaFiltration |
| HDI | Hexamethylene Di Isocyanate |
| HDITCP | 1,1',3,3,3',3'-Hexamethyl-4,4',5,5'-Dibenzo-2,2' Indo Tricarbo Cyanine Percholoate |
| HDL | High Density Lipoprotein |
| HDM | house dust mite |
| HDN | Hydro De Nitrogenation |
| HDODA | Hexane Di Ol Di Acrylate |
| HDPCVD | High Density Plasma Chemical Vapor Deposition |
| HDPE | High Density Poly(ethylene) |
| HDS | Hydro De Sulfurization |
| HDS Onco. | Hepatic Delivery System |
| HDT | Heat Deflection Temperature |
| HDV | Hepatitis Delta Virus |
| HDW | Hydro De Waxing |
| HDX | Hydrogen Deuterium Exchange |
| He | Hexyl |
| HE | Human Epididymis |
| HEA | Hydroxy Ethyl Acrylate |
| HEC | Hydroxy Ethyl Cellulose |
| HEDPA | 1-Hydroxy Ethylidene-1-Di Phosphonic Acid |
| HEDTA | Hydroxy Ethylethylene Diamine Triacetic Acid |
| HEFA | Hydroprecessed Esters & Fatty Acids |
| HEFH | HEterozygous Familial Hypercholesterolemia |
| HEK | Human Embryonic Kidney |
| HEMA | 2-Hydroxy Ethyl Meth Acrylate |
| HEMC | Hydroxy Ethyl Methyl Cellulose |
| HEPA | High-Efficiency Particulate Absorbing |
| HEPES | N-2-Hydroxy Ethyl Piperazine-N'-2-Ethane Sulfonic acid |
| HER | HERegulin |
| HER | Human EGF Receptor |
| HERG | Human Ether-a-go-go-Related Gene (Cardiology) |
| HERV | Human Endogenous Retro Virus |
| HES | Human Embryonic Stem (cell) |
| HES | Hydroxy Ethyl Starch |
| HES | Hyper Eosinophilic Syndrome |
| HESC | Human Embryonic Stem Cell |
| HESCA | Human Embryonic Stem Cell Antigen |
| HETE | Hydroxy Eicosa Tetra Enoic acid |
| HEV | Hepatitis E Virus |
| HEV | Hybrid Electric Vehicle |
| HEV | High Energy Visible |
| HF | Heart Failure |
| HFA | Hydro Fluoro Alkane (Propellant) |
| HFAC | Hexa Fluoro Acetyl Acetonate |
| HFC | Hydro Fluoro Carbon |
| HFE | Hydro Fluoro Ether |
| HFmrEF | HF with Mid-Range Ejection Fraction |
| HFO | H F Olefin |
| HFOT | High Flow Oxygen Therapy |
| HFP | Hexa Fluoro Propene |
| HFPDDA | 1,1,5,5-tetra Hydrohexa Fluoro Pentane-1,5-Diol Di Acrylate |
| HFPE | Hydrogen Fluoro Poly Ether |
| HFpEF | HF with Preserved Ejection Fraction |
| HFPO | Hexa Fluoro Propylene Oxide |
| HFrEF | HF with reduced Ejection Fraction |
| HFRR | High-Frequency Reciprocating Rig |
| HFS | Hydro Fluo Silicic acid (H2SiF6) |
| HGBL | High-Grade B–cell Lymphoma |
| HGBV | Hepatitis GB Virus |
| HGD | High Grade Dysplasia |
| HGE | Human Granulocytic Ehrlichiosis (Infectious disease) |
| HGF | Hepatocyte Growth Factor |
| HGF | Human Growth Factor |
| HGF/SF | Hepatocyte Growth Factor Scatter Factor |
| hGH | Human Growth Hormone |
| HGP | Human Genome Project |
| HGPS | Hutchinson Gilford Progeria Syndrome |
| HGSOC | high grade serous ovarian cancer |
| HGV | Hepatitis G Virus |
| hHF | hospitalisation for Heart Failure |
| HHMI | Howard Hughes Medical Institute (USA) |
| HHT | Hereditary hemorrhagic telangiectasia |
| hHV | Human Herpes Virus |
| HIB | Haemophillus Influenzae B |
| HIBM | Hereditary Inclusion Body Myopathy |
| HIC | Hydrophobic Interaction Chromatography |
| HIF | Hypoxia Inducible Factor |
| HIF-PH | Hypoxia-Inducible Factor-Prolyl Hydroxylase |
| HIFU | High Intensity Focused Ultrasound |
| HII | Household, Industrial, Institutional |
| HIL | Hole Inj. Layer |
| HIP | Heptane (boiling) Insoluble Polypropylene |
| HIPS | High Impact Poly Styrene |
| HIPT | Hexa Iso Propyl Terphenyl |
| HIT | Histamine In Tolerance |
| HIT | Heparin Induced Thrombocytopenia |
| HIT-IT | Highly Innovative Tactics to Interrupt Transmission (AIDS) |
| HIV | Human Immunodeficiency Virus |
| HK | Hexo Kinase |
| HKGF | Human Keratinocyte Growth Factor |
| HKR | Hydrolytic Kinetic Resolution |
| HL | Hodgkin Lymphoma |
| HLA | Human Leukocyte Antigen |
| HLB | Hydrophilic Lipophilic Balance |
| HLGAG | Heparin sulfate-Like Glycos Amino Glycans |
| HLGAG | Heparan sulfate-Like Glycos Amino Glycans |
| HLM | heart-lung machine |
| HMA | Hot Melt Adhesive |
| HMA Onco. | HypoMethylating Agent |
| HMAF | Hydroxy Methyl Acyl Fulvene (Oncology) |
| HMB | Hexa Methonium Bromide |
| HMB WH | Heavy Menstrual Bleeding |
| HMBA | 2-Hydroxy-4-(Methylthio)Butanoic Acid (Animal Nutrition) |
| HMBN | 2-Hydroxy-4-(Methylthio) Butyro Nitrile (animal nutrition) |
| HMC | Human to Machine Communication |
| HMD | Hexa Methylene Diamine |
| HMD | Hyaline Membrane Disease |
| HMDA | Hexa Methylene Di Amine |
| HMDC | Hexa Methylene Diamine Carbamate |
| HMDS | Hexa Methyl Di Silazane |
| HMF | Hydroxyl-Methyl-Furfural |
| HMG | High Mobility Group (domain protein) |
| HMG CoA | Hydroxy Methyl Glutaryl Coenzyme A |
| HMGB | High Mobility Group Box |
| HMI | Hexa Methylene Imine |
| HMMM | Hexa Methoxy Methyl Melamine |
| HMO | Human Milk Oligosaccharide |
| HMPSA | Hot Melt Pressure Sensitive Adhesive |
| HMPV | Human Meta Pneumo Virus |
| HMS-PP | High Melt Strength Poly Propylene |
| HNE | Human Neutrophil Elastase |
| HNIS | Human Na Iodide Symporter |
| HNL | Hydroxy Nitrile Lyase |
| HNRNP | Heterogeneous Nuclear Ribo Nucleo Protein |
| HNSCC | Head & Neck Squamous Cell Cancer |
| Ho | Holmium |
| HO Rare D. | heterotopic ossification |
| HOA | Hereditary Orotic Aciduria |
| HOFH | HOmozygous Familial Hypercholesterolemia |
| HOMO | Highest Occupied Molecular Orbital |
| HOSINF | Horizontal Silicon Nitride Furnace (Microelectronics) |
| HP | Hardwood Plywood |
| HP Infecti | Helicobacter Pylori |
| HP Nephro | HyperPhosphatemia |
| HPA | Hydroxy Propionic Acid |
| HPA | Hyper Phenyl Alaninemia |
| HPA | Hypothalamo Pituitary-Adrenal |
| HPAI | High Potency Active Ingredients (Pharma.) |
| HPAPI | Highly Potent API |
| HPC | Hydroxy Propyl Cellulose |
| HPC | Hydro Processing Catalyst (refinery catalyst) |
| HPC | Halo Propargyl Compound |
| HPC Comput | High Performance Computing |
| HPDE | 4-Hydroxy-4'-(2,3,4,5,6-Pentafluorobenzoyl) Diphenyl Ether |
| HPFC | High Performance FLASH Chromatography |
| HPHT | High Pressure High Temperature |
| HPLC | High Pressure Liquid Chromatography |
| HPLC | High Performance Liquid Chromatography |
| HPMA | Hydroxy Propyl Meth Acrylate |
| HPMA | Hydroxy Propyl Meth Acrylamide |
| HPMC | Hydroxy Propyl Methyl Cellulose |
| HPMC | Hydroxy Propyl Methyl Cellulose |
| HPMCAS | Hydroxy Propyl Methyl Cellulose Acetate Succinate |
| HPMCP | Hydroxy Propyl Methyl Cellulose Phthalate |
| HPMCP | Hydroxy Pr Me Cellulose Phthalate |
| HPMPC | (S)-1-(3-Hydroxy-2-Phosphonyl-Methoxy Propyl) Cytosine |
| HPP | Hexahydro Pyrimido Pyrimidine |
| HPPD | 4-Hydroxy Phenyl Pyruvate Dioxygenase |
| HPPE | High Pressure Poly Ethylene |
| HPPO | Hydrogen Peroxide Propylene Oxide |
| HPR | High Productivity Research |
| HPSK | Human Prostate Specific Kallikrein |
| HPT | Hyper Para Thyroidism |
| HPTLC | High Performance TLC |
| HPV | Human Papilloma Virus |
| HPV | Hydrogen Peroxide Vapour |
| HQ | Hydro Quinone |
| HR | Heptad Repeat (protein domains) |
| HR | Hormone Receptor |
| HR Cardio. | Heart Rate |
| HR Country | Croatia |
| HRA | Halogen Resistant Azole (Water Treatment) |
| HRD | homologous recombination deficiency |
| HRE | Hypoxia Response Element |
| HRIM | High-Resolution Ion Mobility |
| HRM | Human Resources MAN. |
| HRP | Horse Radish Peroxidase |
| HRPC | Hormone Refractory Prostate Cancer |
| HRR | homologous recombination repair |
| HRS | Hepato Renal Syndrome |
| HRT | Hormone Replacement Therapy |
| HRV | Human Rota Virus |
| HS | High Solids |
| HS | Heat Set |
| HS Derma. | Hidradenitis Duppurativa |
| HSA | Human Serum Albumin |
| HSBC | Hydrogenated Styrenic Block Copolymer |
| HSC | Hematopoietic Stem Cell |
| HSCT | Hematopoietic Stem-Cell Transplantation |
| HSD | Hydroxy Steroid Dehydrogenase |
| HSDD | Hypoactive Sexual Desire Disorder |
| HSE | Health, Safety, Environment |
| HSP | Heat Schock Protein |
| HSP | Heptane (boiling) Soluble Polypropylene |
| HSQ | Hydrogen Silses Quioxane |
| HSV | Herpes Simplex Virus |
| HT | Hydroxy Tryptamine [5-HT; Serotonin] |
| HT | High Throughput |
| HT Rare DI | hereditary tyrosinemia |
| HTA | Hexadecyl Trimethyl Ammonium |
| HTE | High Throughput Experimentation |
| HTEP | High Throughput Electro Physiology |
| HTG | Human Thyro Globulin |
| HTG | Hyper Tri Glyceridemia |
| HTL | Helper T Cells |
| HTLV | Human T-cell Lymphotropic Virus |
| HTN | High Temp. Nylon |
| HTS | High Throughput Screening |
| HTS | High Temperature Superconductors |
| HUAE | Human Umbilical Artery Endothelial |
| HUB | Heavy Uterine Bleeding |
| HUS | Hemolytic Uremic Syndrome |
| HUVE | Human Umbilical Vein Endothelial |
| HUVEC | Human Umbilical Vein Endothelial Cells |
| HVA | Homo Vanillic Acid |
| HVAC | Heating Ventilating and Air Conditioning |
| HZ | Herpes Zoster |