Asymptomatic

Asymptomatic (or clinically silent) is an adjective categorising the medical conditions (i.e., injuries or diseases) that patients carry but without experiencing their symptoms, despite an explicit diagnosis (e.g., a positive medical test).
Pre-symptomatic is the adjective categorising the time periods during which the medical conditions are asymptomatic.
Subclinical and paucisymptomatic are other adjectives categorising either the asymptomatic infections (i.e., subclinical infections), or the psychosomatic illnesses and mental disorders expressing a subset of symptoms but not the entire set an explicit medical diagnosis requires.
Examples
An example of an asymptomatic disease is cytomegalovirus (CMV) which is a member of the herpes virus family. "It is estimated that 1% of all newborns are infected with CMV, but the majority of infections are asymptomatic." (Knox, 1983; Kumar et al. 1984) In some diseases, the proportion of asymptomatic cases can be important. For example, in multiple sclerosis it is estimated that around 25% of the cases are asymptomatic, with these cases detected postmortem or just by coincidence (as incidental findings) while treating other diseases.
Importance
Knowing that a condition is asymptomatic is important because:
It may be contagious, and the contribution of asymptomatic and pre-symptomatic infections to the transmission level of a disease helps set the required control measures to keep it from spreading.
It is not required that a person undergo treatment. It does not cause later medical problems such as high blood pressure and hyperlipidaemia.
Be alert to possible problems: asymptomatic hypothyroidism makes a person vulnerable to Wernicke–Korsakoff syndrome or beri-beri following intravenous glucose.
For some conditions, treatment during the asymptomatic phase is vital. If one waits until symptoms develop, it is too late for survival or to prevent damage.
Mental health
Subclinical or subthreshold conditions are those for which the full diagnostic criteria are not met and have not been met in the past, although symptoms are present. This can mean that symptoms are not severe enough to merit a diagnosis, or that symptoms are severe but do not meet the criteria of a condition.
List
These are conditions for which there is a sufficient number of documented individuals that are asymptomatic that it is clinically noted. For a complete list of asymptomatic infections see subclinical infection.
Balanitis xerotica obliterans
Benign lymphoepithelial lesion
Cardiac shunt
Carotid artery dissection
Carotid bruit
Cavernous hemangioma
Chloromas (Myeloid sarcoma)
Cholera
Chronic myelogenous leukemia
Coeliac disease
Coronary artery disease
Coronavirus disease 2019
Cowpox
Diabetic retinopathy
Essential fructosuria
Flu or Influenza strains
Folliculosebaceous cystic hamartoma
Glioblastoma multiforme (occasionally)
Glucocorticoid remediable aldosteronism
Glucose-6-phosphate dehydrogenase deficiency
Hepatitis
Hereditary elliptocytosis
Herpes
Heterophoria
Human coronaviruses (common cold germs)
Hypertension (high blood pressure)
Histidinemia
HIV (AIDS)
HPV
Hyperaldosteronism
hyperlipidaemia
Hyperprolinemia type I
Hypothyroidism
Hypoxia (some cases)
Idiopathic thrombocytopenic purpura
Iridodialysis (when small)
Lesch–Nyhan syndrome (female carriers)
Levo-Transposition of the great arteries
Measles
Meckel's diverticulum
Microvenular hemangioma
Mitral valve prolapse
Monkeypox
Monoclonal B-cell lymphocytosis
Myelolipoma
Nonalcoholic fatty liver disease
Optic disc pit
Osteoporosis
Pertussis (whooping cough)
Pes cavus
Poliomyelitis
Polyorchidism
Pre-eclampsia
Prehypertension
Protrusio acetabuli
Pulmonary contusion
Renal tubular acidosis
Rubella
Smallpox (extinct since the 1980s)
Spermatocele
Sphenoid wing meningioma
Spider angioma
Splenic infarction (though not typically)
Subarachnoid hemorrhage
Tonsillolith
Tuberculosis
Type II diabetes
Typhus
Vaginal intraepithelial neoplasia
Varicella (chickenpox)
Wilson's disease
Millions of women reported lack of symptoms during pregnancy until the point of childbirth or the beginning of labor; they didn't know they were pregnant. This phenomenon is known as cryptic pregnancies.
See also
Symptomatic
Subclinical infection
References
Medical terminology
Symptoms