Medical Language

Commonly misspelled names

For a more thorough compilation of eponymous disease names with proper punctation and spelling, please see the National Human Genome Research Institute’s Genetic Disorders page.

Alzheimer’s disease

Not Alzheimer disease. Use Alzheimer’s disease on the first reference; just Alzheimer’s (without the word “disease”) is acceptable for subsequent references on the same webpage or document. The abbreviation AD is acceptable on second reference if it is used along with the first reference: Alzheimer’s disease (AD).

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) was once commonly known as Lou Gehrig’s disease, after the famous ballplayer in the 1940s who retired because of the disease. NIH doesn’t refer to Lou Gehrig’s disease in our web content. You may write “also known as Lou Gehrig’s disease” when writing resources intended for the public, e.g., MedlinePlus. (Some people’s only point of reference to the disease may be through the name Lou Gehrig's).

Creutzfeldt-Jakob disease

Not Creutzfeldt-Jakob’s disease.

Crohn’s disease

Not Crohns disease, Crohn disease, nor Crohns’ disease.

Down syndrome

Not Down’s syndrome nor Down’s.

Down syndrome is a condition or a syndrome, not a disease. People have Down syndrome; they do not suffer from it and are not afflicted by it. Use person-first language: a child with Down syndrome.

Graves’ disease

Not Grave’s disease.

Hashimoto’s disease

Not Hashimotos disease or Hashimoto disease.

Hodgkin lymphoma and non-Hodgkin lymphoma

Not Hodgkin’s lymphoma. The abbreviation HL is acceptable on second reference if it is used along with the first reference: Hodgkin lymphoma (HL). The abbreviation NHL is acceptable for non-Hodgkin lymphoma.


AP Stylebook: mpox

While the virus is still called monkeypox because the International Committee on the Taxonomy of Viruses has yet to update their entry, use mpox or the virus that causes mpox, unless scientifically essential. Mpox is not capitalized unless it begins a sentence.

Myalgic encephalomyelitis/chronic fatigue syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome, commonly known by its abbreviation ME/CFS, is often misspelled, and sometimes referred to as “chronic fatigue,” which is a symptom but not the name of the disease. Myalgic encephalomyelitis/chronic fatigue syndrome is not capitalized unless it begins a sentence.

Parkinson’s disease

Not Parkinson disease. Use Parkinson’s disease on the first reference and then the acronym PD for subsequent references. Parkinson’s without the word “disease” is rarely used in NIH writing but is acceptable.


COVID-19, SARS-CoV-2 coronavirus

AP Stylebook: coronaviruses

COVID-19 (coronavirus disease 2019) is an infectious disease caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Use COVID-19 when referring to the disease and SARS-CoV-2, or the virus that causes COVID-19, when referring to the virus itself. Do not use coronavirus to refer to the disease or as a synonym for COVID-19. Always capitalize all the letters in COVID-19 (not Covid-19 or covid-19). Do not shorten COVID-19 to COVID.

Coronaviruses are a large family of viruses that usually cause mild to moderate upper-respiratory tract illnesses in humans. However, three coronaviruses have caused more serious and fatal disease in people: SARS-associated coronavirus, MERS-CoV, and SARS-CoV-2.


PASC stands for post-acute sequelae of SARS-CoV-2 and is a term that scientists are using to study the potential consequences of a SARS-CoV-2 infection.

One of these consequences is referred to as Long COVID — when COVID-19 symptoms last weeks or months after the acute infection has passed. Do not use the term long-haulers when referring to people who have Long COVID. PASC and Long COVID are not interchangeable terms. Use “long COVID” for press releases, per AP style, but “Long COVID” for all other NIH writing.

Multisystem inflammatory syndrome in children (MIS-C) is a condition in which different body parts can become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs. The cause of MIS-C is not yet known, but many children who develop MIS-C previously had COVID-19.

Vaccine hesitancy vs. anti-vax

AP Stylebook: anti-vaxxer
Use vaccine hesitant, vaccine hesitancy, or someone opposed to vaccines instead of anti-vaxxers, anti-vax, or anti-vaccine. If necessary in a direct quote, explain it.


Blood glucose vs. blood sugar

Use blood glucose instead of blood sugar. On first mention of blood glucose, you may include “also called blood sugar,” offset by commas.


Hypoglycemia, also called low blood glucose, occurs when the level of glucose in your blood drops below what is healthy for you. Low blood glucose should follow hypoglycemia, set off with commas. Use hypoglycemia on first reference.

Avoid describing blood glucose as too low or normal. Preferred terms are low for you or below what is healthy for you.

Example: Your number might be different, so check with your doctor or health care team to find out what blood glucose level is low for you.


Use take insulin instead of use insulin when writing about a person administering or injecting insulin into the body.


Always list diabetes first when listing diabetes and prediabetes.

Type 1, type 2 diabetes

Type 1 and type 2 diabetes should be lowercase unless beginning a sentence, per the American Diabetes Association.

This page last reviewed on January 17, 2024