Diagnosis (from the Greek words dia = by and gnosis = knowledge) is the process of identifying a disease by its signs, symptoms and results of various diagnostic procedures. The conclusion reached through that process is also called a diagnosis. A disease is an abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person afflicted or those in contact with the person. ... In medicine, a sign is a feature of disease as detected by the doctor. ... The term symptom (from the Greek syn = con/plus and pipto = fall, together meaning co-exist) has two similar meanings in the context of physical and mental health: A symptom may loosely be said to be a physical condition which shows that one has a particular illness or disorder (see...

The term "diagnostic criteria" designates the combination of symptoms which allows the doctor to ascertain the diagnosis of the respective disease.

Typically, someone with abnormal symptoms will consult a physician, who will then obtain a history of their present illness and examine them for signs of disease. The physician will formulate a hypothesis of likely diagnoses and in many cases will obtain further testing to confirm or clarify the diagnosis before proceeding to render treatment. Physician examining a child A physician is a person who practices medicine. ... Look up Therapy in Wiktionary, the free dictionary Therapy (in Greek: θεραπεία) or treatment is the attempted remediation of a health problem, usually following a diagnosis. ...

Forms of testing commonly performed are urine tests, stool samples, saliva samples, blood tests, medical imaging, electrocardiogram, urinalysis, hydrogen breath test and, occasionally, biopsy. A urinalysis (or UA) is an array of tests performed on urine, usually used in medical diagnosis. ... Human feces vary significantly in appearance, depending on the state of the whole digestive system, influenced by diet and health. ... Saliva, often informally known as spit, is the moist, clear, and usually somewhat frothy substance produced in the mouths of some animals, including humans. ... Blood tests are laboratory tests done on blood to gain an appreciation of disease states and the function of organs. ... It has been suggested that this article or section be merged into Radiology. ... Lead II An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... A urinalysis (or UA) is an array of tests performed on urine and one of the most common methods of medical diagnosis. ... A Hydrogen Breath Test (or HBT) is used as a clinical medical diagnosis for people with irritable bowel syndrome, and common food intolerances. ... A biopsy (in Greek: bios = life and opsy = look/appearance) is a medical test involving the removal of cells or tissues for examination. ...

The list of most likely and possible diagnoses based on available information is called a differential diagnosis; the final diagnosis is only arrived at after other diseases on this list have been eliminated through further investigations or consultations. In medicine, differential diagnosis (sometimes abbreviated DDx) is the systematic method physicians use to identify the disease causing a patients symptoms. ...

History

The history of medical diagnosis began in earnest from the enlightened days of Hippocrates in ancient Greece but is far from perfect despite the enormous bounty of information made available by medical research including the sequencing of the human genome. The practice of diagnosis continues to be dominated by theories set down in the early 1900s. This article or section is in need of attention from an expert on the subject. ... Ancient Greece is the period of Greek history spanning much of the Mediterranean and Black Sea basins and lasting for close to a millennium, until the rise of Christianity. ... In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. ... The human genome is the genome of Homo sapiens. ... // Events and Trends Technology First flight by the Wright brothers, December 17, 1903. ...

Ancient Greece

Over two thousand years ago, Hippocrates recorded the association between disease and heredity. In similar fashion, Pythagoras noted the association between metabolism and heredity (allergy to Fava beans). The medical community, however, has only recently acknowledged the importance of genetics and its relevance to mainstream medicine. Pythagoras (approximately 580 BC–500 BC, Greek: Πυθαγόρας) was an Ionian (Greek) mathematician and philosopher, founder of the mysterious religious and scientific society called Pythagoreans, and is known best for the Pythagorean theorem which bears his name. ... Santorio Santorio (1561-1636) in his steelyard balance, from Ars de statica medecina, first published 1614 Metabolism (from μεταβολισμος (metabolismos)) is the biochemical modification of chemical compounds in living organisms anggjgjhnd cell (b). ... Heredity (the adjective is hereditary) is the transfer of characteristics from parent to offspring, either through their genes or through the social institution called inheritance (for example, a title of nobility is passed from individual to individual according to relevant customs and/or laws). ... Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ... Medicine is the branch of health science and the sector of public life concerned with maintaining human health or restoring it through the treatment of disease and injury. ...

The Oslerian ideal

The ideals of William Osler who innovated the practice of medicine in the early 1900s were based on the principles of the diagnosis and treatment of disease. According to Osler, the functions of a physician were to be able to identify disease and its manifestations, understand its mechanisms, how it may be prevented and how it may be cured. For his medical students he believed that the best textbook was the patient himself – analysis of morbid anatomy and pathology were the keys. The Oslerian ideal continues today, as the basis of the Doctor’s strategy is, "What disease does this patient have and what is the best way for treatment?" The emphasis is on the classification of the disease in order to use the remedies available for its effects to be reversed or ameliorated. The human being in question is representative of a class of people with this type of disease whereas the biological individuality of this person is not given any great weight. The Four Doctors by John Singer Sargent, 1905, depicts the four physicians who founded Johns Hopkins Hospital. ... A disease is an abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person afflicted or those in contact with the person. ... Physician examining a child A physician is a person who practices medicine. ... Anatomical drawing of the human muscles from the Encyclopédie. ... Pathology (from Greek pathos, feeling, pain, suffering; and logos, study of; see also -ology) is the study of the processes underlying disease and other forms of illness, harmful abnormality, or dysfunction. ...

Garrod's view

The successor to William Osler as Regius Professor at Oxford was Archibald Garrod. Garrod echoed the observations of his Greek counterparts of two millennia ago, ...our chemical individualities are due to our chemical merits as well as our chemical shortcomings; and it is more nearly true to say that the factors which confer upon us our predispositions to and immunities from various mishaps which are spoken of as diseases, are inherent in our very chemical structure; and even in the molecular groupings which confer upon us our individualities, and which went into the making of the chromosomes from which we sprang. Considering that the time that he formulated these ideas were the early 1900's, and the knowledge of DNA encoding genes that in turn encoded proteins responsible for bodily structure and functions not being discovered until some fifty years later it took some time before medicine could fully appreciate the fundamental importance of his concept of diagnosis. Sir Archibald Edward Garrod was an English physician who pioneered the field of inborn errors of metabolism. ... This article is about the biological chromosome. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid —usually in the form of a double helix— that contains the genetic instructions specifying the biological development of all cellular forms of life, and most viruses. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...

Present-day Oslerian practice

Whereas Osler laid the founding principles by which medicine should be practiced, Garrod placed these principles in a greater context of a chemical individuality that is inherited and is subject to the mechanisms of evolutionary selection. The Oslerian ideal of medical practice continues to dominate medical philosophy today. The patient is a collective of symptoms to be characterised and analysed algorithmically in order to draw a diagnosis and subsequently produce a strategy of treatment. Medicine is about problems based solutions. In keeping with this philosophy, today's pathology reports provide a momentary snapshot of the patient's biochemical profile, highlighting the end result of the disease process. A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... This article is about biological evolution. ... The term symptom (from the Greek syn = con/plus and pipto = fall, together meaning co-exist) has two similar meanings in the context of physical and mental health: A symptom can be a physical condition which shows that one has a particular illness or disorder (see e. ... Flowcharts are often used to represent algorithms. ... Biochemistry is the chemistry of life. ...

Influence of DNA technology

Garrod's conception of biological individuality was confirmed with the advent of the sequencing of the human genome. Finally the subtle relationship between inheritance, individuality and environment became apparent via the variations detected in DNA. In each patient's DNA lies a script for how their bodies will change and become ill as well as how they will handle the assaults of the environment from the beginning of their life to its end. It is hoped that by knowing a patient's genes that the biological strengths and weaknesses in respect to these assaults will be revealed and disease processes can be predicted before they have the opportunity to manifest. Although knowledge in this area is far from complete, there are already medical interventions based on this. More importantly, the physician, forewarned with this knowledge can guide the patient towards appropriate lifestyle changes to anticipate and mitigate disease processes. Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology is the science of life (from the Greek words bios = life and logos = word). ...

Hypothesis testing

History taking is a fluid process that adapts to the information as it is presented. Almost invariably the patient presents with a complaint. Even the unconscious patient presents with the implicit complaint of being unconscious. This presenting complaint leads to the formation of hypotheses. Rather than consider the myriad of diseases that could afflict the patient, the physician narrows down the possibilities to those conditions likely to account for the presenting complaint. The history taking then proceeds to test these hypotheses, often narrowing down the diagnosis within a few questions. Sometimes the initial hypotheses are ruled out and the physician must then move on to look at other hypotheses or multiple ones. Occam's razor is then invoked to attempt to simplify the number of provisional diagnoses and it is only with some reluctance that a physician will make several provisional diagnoses to explain the symptoms elicited. To meet Wikipedias quality standards, this article or section may require cleanup. ... William of Ockham Occams razor (also spelled Ockhams razor) is a principle attributed to the 14th-century English logician and Franciscan friar William of Ockham. ...

The physician then moves on to the physical examination. However, the hypothesis testing does not end at this point. Signs may confirm the provisional diagnosis or cause the physician to consider the question further and even lead to more questioning. An unexpected finding on examination may cause the physician to reconsider the initial diagnosis.

At this point the physician usually has at least a differential diagnosis and probably a provisional diagnosis if not a firm diagnosis. Further tests are then requested, in part to confirm or disprove the diagnosis but also to document the status at that time and before treatment is started. Consultations with other physicians and specialists in the field may be sought. In medicine, differential diagnosis (sometimes abbreviated DDx) is the systematic method physicians use to identify the disease causing a patients symptoms. ...

Treatment itself may indicate a need for review of the diagnosis if there is a failure to respond to treatments that would normally work.

Despite all of these complexities, most consultations are relatively brief, partly because many diseases are common and pattern recognition allows the physician to recognize the diagnosis early, but also because the decision trees of most hypothesis testing are relatively short. Pattern recognition is a field within the area of machine learning. ...

See also

Abduction, or abductive reasoning, is the process of reasoning to the best explanations. ... The term diagnosis of exclusion refers to a medical condition whose presence cannot be established with complete confidence from examination or testing. ... Diagnosis-related groups (DRGs) are a classification of hospital case types into groups expected to have similar hospital resource use. ... It has been suggested that DSM cautionary statement be merged into this article or section. ... An explanation is a statement which points to causes, context and consequences of some object (or process, state of affairs etc. ... Wikipedia does not yet have an article with this exact name. ... Wikipedia does not yet have an article with this exact name. ... Nosology (in Greek Nosos = Disease) is a branch of medicine that deals with classification of diseases. ... A nursing diagnosis is a standardized statement about the health of a client (who can be an individual, a family, or a community) for the purpose of providing nursing care. ... Similar to induction, but predicated on a known relationary rule(s) and an observation(s). ...

External links

• Differential Diagnosis