Pathology Abbreviated: A Long Review of Short Terms
Archives of Pathology and Laboratory Medicine
Jules J. Berman, PhD, MD Context. Abbreviations are used frequently in pathology reports and medical records. Efforts to identify and organize free-text concepts must correctly interpret medical abbreviations. During the past decade, the author has collected more than 12000 medical abbreviations, concentrating on terms used or interpreted by pathologists. Objective. The purpose of the study is to provide readers with a listing of abbreviations. The listing of abbreviations is reviewed for the purpose of determining the variety of ways that long forms are shortened. Design. Abbreviations fell into different classes. These classes seemed amenable to distinct algorithmic approaches to their correct expansions. A discussion of these abbreviation classes was included to assist informaticians who are searching for ways to write software that expands abbreviations found in medical text. Classes were separated by the algorithmic approaches that could be used to map abbreviations to their correct expansions. A Perl implementation was developed to automatically match expansions with Unified Medical Language System concepts. Measurements. The abbreviation list contained 12097 terms; 5772 abbreviations had unique expansions. There were 6325 polysemous abbreviation/expansion pairs. The expansions of 8599 abbreviations mapped to Unified Medical Language System concepts. Three hundred twenty-four abbreviations could be confused with unabbreviated words. Two hundred thirteen abbreviations had different expansions depending on whether the American or the British spellings were used. Nine hundred seventy abbreviations ended in the letter s. Results. There were 6 nonexclusive groups of abbreviations classed by expansion algorithm, as follows: (1) ephemeral; (2) hyponymous; (3) monosemous; (4) polysemous; (5) masqueraders of common words; and (6) fatal (abbreviations whose incorrect expansions could easily result in clinical errors). Conclusion. Collecting and classifying abbreviations creates a logical approach to the development of class-specific algorithms designed to expand abbreviations. A large listing of medical abbreviations is placed into the public domain. The most current version is available at http://www.julesberman.info/abbtwo.htm Expanding and removing the ambiguity from abbreviations is one of the more challenging issues in natural language parsing. Collecting and classifying abbreviations is a necessary exercise. It is the first step toward developing algorithmic strategies to assign the correct expansions for medical abbreviations parsed from text. Most medical abbreviations were no doubt invented as time-savers for health professionals. These same abbreviations can waste the time of those persons tasked with organizing, indexing, searching, or interpreting medical text. Those reading a medical record are expected to know that ga occurring within an obstetric history usually means gestational age, while ga occurring within a dermatologic history usually means granuloma annulare. Automatic indexers and machine translators of medical text require large and accurate lists of medical abbreviations and accurate algorithms to find abbreviations within text and to map the abbreviations to their correct expansions. Also required is an understanding of the types of problems encountered when abbreviations are expanded. A PubMed search on biomedical AND abbreviations reveals that most literature contributions to the field consist of outraged editorials and letters decrying the inappropriate use of abbreviations. Strangely, the problem of correctly expanding free-text abbreviations into standard terminology has received very little serious attention in the medical informatics literature.1�3 In an early study in which the words from medical reports were enumerated, there was no mention whatsoever of abbreviations.4 Recently, Liu et al3 studied a set of abbreviations that could be algorithmically extracted from the Unified Medical Language System (UMLS), extracting 163666 abbreviation/expansion pairs.3 These authors noted that many abbreviations have multiple different expansions and that the expansions cannot always be disambiguated based on separating abbreviations by their knowledge domain. Liu et al3 indicated that methods are needed to remove the ambiguity from ambiguous abbreviations. The current study involves a hand-annotated listing of about 12000 abbreviations, many of which were encountered in pathology reports and pathology literature. Medical abbreviations come in 2 forms: acronyms and shortened words. Acronyms are character strings usually composed from the first letters of a text phrase. Many acronyms are noun phrases. A straightforward example is CABG, which stands for coronary artery bypass graft. There are relatively few abbreviations for adjectives. Examples include the following: AP = anterior-posterior; L = left. There are almost no abbreviations for verbs. A shortened form is a subset of letters taken from a word; the letters almost always maintain the same relative order as their original appearance in the word, and usually they are taken from the beginning of the word. An example is ceph, which stands for cephalosporin. In this article, I provide a useful resource to pathology informaticians, a listing of more than 12000 abbreviations organized by polysemy. Upon review of the abbreviations, the author noted that the abbreviations could be classified by the algorithmic approaches needed for their correct interpretation. Such a classification may be of value to informaticians who are designing software to expand medical abbreviations. The review of abbreviations and the discussion of the classes of abbreviations are provided with the expectation that they may have value for programmers in the field. The implementations of classed algorithms will be the subject of future efforts. MATERIALS AND METHODS All abbreviations (circa 12000) collected for this article, along with the Perl script that itemizes the abbreviations, is available at http://www.julesberman.info/abbtwo.htm This resource is placed in the public domain by the author with no implied or expressed warranties. The UMLS is available (at no cost) from the National Library of Medicine's web site (http://www.nlm.nih.gov/research/umls/). The 2001 UMLS was used, and a valid user's license was obtained. The MRCON file, containing about 1.5 million concepts, was used to match against the expansions of abbreviations listed in the author's abbreviation file. RESULTS Counting abbreviations can be very revealing. Table 1 summarizes the feature data of the supplemental list of annotated abbreviations. The following observations from the list illustrate the difficulties that would be encountered by any direct algorithmic approach to predicting abbreviations from expansions, or vice versa.
Table 1. Summary of the List of Abbreviations (http://www.julesberman.info/abbtwo.htm)
Abbreviations That Are Neither Acronyms or Shortened Forms of Expansions Sometimes short forms contain letters not found in the long form of the abbreviated word. For example, the short form of the word diagnosis is dx, although no x is contained therein. The same applies to the x in tx, the abbreviation for therapy, but not the x in the TX that stands for Texas. For that matter, the short form of times is an x, relating to the notation for the multiplication operator. Roman numerals I, V, X, and L and M are abbreviations for words assigned to numbers, but they are not characters included in the expanded words. EKG is the abbreviation for electrocardiogram, a word bereft of the letter K. The K comes from the German orthography. There is no letter q in subcutaneous, but the abbreviation for the word is sometimes subq and never subc. Medical records borrow heavily from the Periodic Table. Is KCl an abbreviation for potassium chloride or is it the full term for the chemical symbol? What about Calc for calcium. Calc is indeed a short form, but any chemist would tell you that it is the wrong form (forme fruste). What about EtOH? Nurses and doctors perform alchemy (not chemistry) to convert ethanol to etoh. Certainly EtOH is a type of abbreviation, but the linguistic method employed to create the abbreviation is obscure. Abbreviations That Are Sometimes Both Acronyms and Shortened Forms The letter l (for the word left) is both an acronym and a shortened form. This is true for almost all single-letter abbreviations. Another term that is difficult to assign as either acronym or short form is DNA (deoxyribonucleic acid). DNA may well be an acronym, because the D is the first letter of deoxyribonucleic and the A is the first letter of acid, but the N comes up in the middle of a deoxyribonucleic. The letter N is the first letter of a word that could stand as an individual word (nucleic), even though it does not in this case. DNA can also be thought of as a simple shortened form of a long word, the same way that cmpd is a shortened form of the word compound. In both, the letters are pulled from their order of appearance in the full word but are chosen from scattered sites within the word. An example of a mixed acronym/abbreviation is dsv, representing the dermatome of the fifth sacral nerve. Here a preposition, an article, and a noun (of, the, nerve) have been dropped for the abbreviation, the order or the acronym components has been changed (dermatome sacral fifth), an ordinal has been changed to a cardinal (fifth changed to five), and the cardinal has been shortened to its roman numeral equivalent (v). Prepositions and Articles Retained in an Acronym When forming an acronym from a phrase, it is difficult to guess when to use or abandon prepositions. Many acronyms exclude prepositions and articles. CAP is the acronym for College of American Pathologists, snubbing the of. Other abbreviations are not so snobbish (DOB = date OF birth). The word NIH (for National Institutes of Health) denies any generosity to its sole preposition. Sometimes both forms are accepted abbreviations (eg, edd = estimated date of delivery and edod = estimated date of delivery). Single Expansions With Multiple Abbreviations Just as abbreviations can map to many different expansions, the reverse can occur. For instance, high-grade squamous intraepithelial lesion can be abbreviated as HGSIL or HSIL. Xanthogranulomatous pyelonephritis can be abbreviated as xgp or xgpn. Angioimmunoblastic lymphadenopathy can be abbreviated as abl, ail, or aiml. Nonsense Abbreviations ANNL and ANLL represent the phrase acute nonlymphoblastic leukemia. It is impossible to imagine how the term ANNL ever became the abbreviation for a phrase that contains a solitary letter N, but this abbreviation appears occasionally in the pathology literature. The term PT-LPD represents the phrase posttransplantation lymphoproliferative disorders. The only location for a hyphen in the expansion is between the letters p and t. Why does the acronym move the hyphen? The term GNU (Gnu is not UNIX) is an example of a self-referring acronym. Fully expanded, this acronym is of infinite length. Although the N and the U expand to words (not Unix), the letter G is forever inscrutable. The expansion for OK is simply okay, the phonetic spelling of the sound made by the pronunciation of the abbreviation. Neither the abbreviation nor the expansion has any obvious entomologic derivation. Common Usage That Confounds Meaning The term TREC is the acronym for text retrieval conference. However, it seems that whenever TREC appears in a sentence, it occurs in the phrase TREC conference (trec.nist.gov/). Clearly, the word conference is redundant in this example. Apparently people would rather attend a TREC Conference than either a Tre Conference or a TREC. Sometimes straightforward abbreviations adopt phonetic forms with features of shibboleths. For instance, the term peripheral neuroectodermal tumors is abbreviated as PNET, but PNET sounds like peanut, and peanut is now the abbreviated form used in conversation and literature for these tumors.5 Examples of other phonetic expansions are cabbage for the phrase coronary artery bypass graft, and the term Tobasco, used for the phrase total abdominal hysterectomy and bilateral oophorectomy. At times a word's abbreviation looks enough like an expansion to goad a spell-checker into action. The word cameleon is an abbreviation for the phrase cytosine arabinoside, high-dose methotrexate, leucovorin, oncovin. Spell-checkers should not replace the abbreviation with a chameleon. Though not a medical abbreviation, the following practice exemplifies the horrors of recursive abbreviations. The term SMETE is the abbreviation for the phrase science, math, engineering, and technology education. The term NSDL is the abbreviation for the term National SMETE Digital Library community (found at www.osti.gov/speeches/asist.html). Assuming that the term requires an abbreviation, wouldn't the form of the abbreviation holding a clue to the identity of the expansion be NSMETEDL? Pejorative Abbreviations Pejorative or disrespectful terms should never appear in the medical record. When they occur, it would be better if they were not expanded: flk = funny looking kid and gomer = get out of my emergency room. Pejorative abbreviations have been omitted from the author's file. Locale-Dependent Abbreviations Americans sometimes forget that most of the English-speaking countries use British English. Americans contribute a minor share of English free-text. So TOF makes no sense as an abbreviation of tracheo-esophageal fistula here in Bethesda, Md, but this abbreviation makes perfect sense in London, where patients may have trancheo-oesophageal fistulas. The term GERD (representing the phrase gastroesophageal reflux disease) makes perfect sense to Americans, but it must be confusing to Australians. COMMENT Classifying Abbreviations by Their Expansion Algorithms Different types of abbreviations create different types of interpretive problems. When a document is parsed into words, it is relatively easy to determine whether a given word string matches a term in a long list of abbreviation/expansion pairs. However, an algorithm is needed to determine if the word string is correctly mapped to its intended expansion. The algorithm used to perform this task may depend on the context of the parsed document word and on the class or classes of abbreviations matching the parsed word. The following classification of abbreviations is chosen to separate abbreviations by the algorithmic tasks required for their accurate selection and expansion. Ephemeral Abbreviations The most common form of abbreviation is the ephemeral abbreviation. The ephemeral abbreviation is invented on the fly by a writer and is intended to exist within a single document. These are the abbreviations that are usually found early in an article as an uppercase string within a parenthetical expression following the first appearance of the expansion. Elsewhere in the article they appear as stand-alone uppercase character strings. Ephemeral abbreviations are typically highly coordinated noun terms that appear sufficiently often within a particular document to justify their creation. For example, a pathology article may contain many references to an unidentified eosinophilic nodule of basement membrane-like material (abbreviated as UENBMM). The author probably has no intention of incorporating the abbreviation into the permanent medical literature. It is easy to build a parser that automatically extracts such terms from text because they are almost always introduced in a structured way (ie, expansion immediately followed by parenthetical abbreviation). The ephemeral abbreviation exists only within a specific document. An algorithm might look for an uppercase string (often enclosed by parentheses) preceded by or following a text phrase, the first letters of which equal or approximate the uppercase string. This text phrase would be the expansion of the ephemeral abbreviation. Whenever the same uppercase word appears later in the same document, it could be tagged with a metadata tag, indicating that the uppercase string is an abbreviation and that its expansion is the previously determined text phrase. The abbreviation and its expansion would disappear at the end of the document. An algorithm for expanding ephemeral abbreviations has been discussed by Liu et al.3 Hyponymous Abbreviations The entity A is a hyponym or subordinate of B if A is a specific kind of B. So poodle is a hyponym of dog. The term HSIL (representing the phrase high-grade squamous intraepithelial lesion) is a hyponym of SIL. The phrase AIDH (representing the phrase atypical intraductal hyperplasia) is a hyponym for IDH (intraductal hyperplasia). In many instances, there are abbreviations for the hyponym, but no abbreviation for the more general term. For example, the term DVT expands to deep vein thrombosis, but there is no medical abbreviation for the phrase venous thrombosis of undetermined depth (ie, no VT). PE stands for the term pulmonary embolus, but E is not in use as an abbreviation for the word embolus. The most common hyponym examples relate to singular/plural forms. After all, every singular form is a hyponym of its plural. So, the term rbc represents the phrase red blood cell. Some people use rbc to refer to either the singular or the plural (because C expands to cell or to cells). But some people prefer to turn the abbreviation into a familiar plural form, rbcs. In many cases, when a plural is added to an abbreviation, people will demarcate the plural form from the singleton by an awkward use of uppercase and lowercase characters. So, erythrocytes may be abbreviated as RBCs. It is also common to engage the possessive form when converting an abbreviation into its plural form (eg, RBC's). This is grammatically the wrong thing to do when the single form does not end in an s. Occasionally, the plural form of an abbreviation is used, even when it defies rational analysis. So, a man with withdrawal symptoms may have the DTs, even though he is only suffering from one case of delirium tremens. What do you do when the single form properly ends with a word that begins with s? The abbreviation for the phrase Hospital Information System is HIS. If you wish to refer to multiple systems, is the plural HISs, HIS, or HISes? One may surmise that all 3 forms occur in nature. Unfortunately, unless the plural abbreviation comes in the form of an uppercase acronym followed by a lowercase s, confusion may arise with acronyms whose last expanded word is syndrome. So, how would you otherwise distinguish Lesch-Nyhan Syndrome (lns) from the plural of the abbreviation of the phrase lymph nodes (lns)? In the supplemental abbreviation file, there were 970 abbreviations ending with s and 245 expansions that included the word syndrome. Single hyponyms of plural forms that do not end with an s are really not a problem. Nobody will care whether a parser expands rbc to red blood cell when the intended expansion was red blood cells. There may be some minor annoyance when tia is expanded to transient ischemic attack when it should have been expanded to transient ischemic attacks. A smart parser can take its contextual cues from the word preceding the abbreviation. Three tia in 24 hours should be mapped to the plural form, while a tia should be mapped to the singular. How do you deal with parsed abbreviations that end with the letter s? Abbreviation hyponyms that have a plural form ending with s can all be put into a single list. If the parser determines that the abbreviation was optimally formatted, with uppercase letters for the abbreviation and a lowercase s at the end, then the parser should only match against the singular hyponym (ie, match TIAs against TIA). In other cases, the parser algorithm may choose to determine from the context of the sentence whether the abbreviation is a plural form. If so, it can look for a match among the list of abbreviations whose plural form ends with an s. If there is a match, that may be sufficient. If there is not a match, the s can be truncated and matches should be sought in the large list of abbreviations not ending with a plural form designated by s. Monosemous Abbreviations The monosemous abbreviation has a unique expansion. Therefore, it is relatively simple to write algorithms that correctly match expansions against abbreviations parsed from medical text. Fortunately, about half of abbreviations (5772 in the supplemental abbreviation file) seem to be monosemous. In general, the longer the abbreviation, the more likely it will be to have a unique expansion. Polysemous Abbreviations Polysemy is the condition whereby a single term has multiple meanings. The most polysemous abbreviation is PA, which has 41 different expansions. There are many different algorithmic approaches to the problem of assigning a correct expansion to a polysemic abbreviation. An algorithm can simply use a frequency of occurrence list for the different possible expansions, choosing the most often�encountered expansion as the correct expansion for any abbreviation. The term PA appearing in a radiology report is much more likely to expand to posterior-anterior than to propionic acid. However, a good algorithm may need to reckon with pulmonary artery as a reasonable alternative. Another algorithm may use the nonabbreviated words found in the paragraph or sentence containing the abbreviation as clues to the abbreviation's intended expansion. UMLS contains long lists of concepts that relate to other concepts. Choosing an expansion (from a list of expansions matching an abbreviation) on a relatedness index is certainly a reasonable approach to dealing with polysemous abbreviations. Abbreviations Masquerading as Words Particularly irksome are abbreviations that map to often-used general words, such as the phrases axillary node dissection (AND), acute lymphocytic leukemia (ALL), optic neuritis (ON), and acanthosis nigricans (AN). The most difficult abbreviations map to commonly used medical terms, such as Acquired Immune Deficiency Syndrome (AIDS), Bornholm Eye Disease (BED), and Expired Air Resuscitation (EAR). Many acronyms will almost always appear as uppercase strings or as strings internally punctuated by periods. For instance, the phrase United States is often abbreviated as US or as U.S., thus distinguishing it from us. But health professionals will not always play by the rules. A pin sometimes lurks in a diaper and sometimes lurks in a prostate (prostatic intraepithelial neoplasia). Nadkarni and coworkers3 noted that some abbreviations are words. They also found that these could not reliably be distinguished based on the uppercase format of the abbreviation, it being too inconsistent to be relied on in medical notes. In the supplemental abbreviation file, there are at least 321 abbreviations that are also common words. A sampling of these masqueraders is listed in Table 2 . The full list of masqueraders would be needed by any algorithm that parses medical text. Certainly, if a word appears in all uppercase letters in a sentence (that is otherwise lowercase), it seems reasonable to assume that the word is an abbreviation. Abbreviations can be matched directly against the list of expansions for the abbreviations that masquerade as words. If a word parsed from medical text matches an abbreviation from the list of abbreviations that masquerade as words, and if the word has no distinguishing format, then an algorithm may be designed to consider the frequency of occurrence of the expansion compared to the frequency of occurrence of the nonabbreviated word. For instance, and will appear more often than axillary node dissection, although ash, the abbreviation for atrial septal hypertrophy, may occur more often than ash, the crumbly black material in the tray. As in the algorithms created for the polysemous abbreviations, it is feasible to look for relatedness between the considered expansion and the words and concepts found in the vicinity of the parsed word.
Table 2. Abbreviations That Masquerade as Words: Sampling From the A's (http://www.julesberman.info/abbtwo.htm)
Fatal Abbreviations: Innocent Victims of Abbreviation Drift It is tempting to assume that abbreviations can be expanded whenever their context is known. For instance, the term cea would expand to the phrase carcinoembryonic antigen in a blood test for a patient who is status postcolectomy for colon cancer. The term CEA would expand to the phrase carotid endarterectomy in a patient whose carotids were being duplex-scanned for occlusive vascular disease. Table 3 contains many instances of abbreviations whose different expansions could not be easily distinguished based on context. Excluded from this list are indistinguishable expansions whose meanings are virtually equivalent (eg, ich = intracranial hemorrhage or intracerebral hemorrhage). Fatal abbreviations probably devolved through imprecise use (a phenomenon I call abbreviation drift). Unfortunately, these expansions are virtually impossible to disambiguate, even by human experts in the knowledge domain. In the case of the fatal abbreviation, it seems appropriate for algorithms not to try to pick the correct expansion but to display an output that lists all the different expansions for the term. For example, The patient has a history of aha; possible expansions are acquired hemolytic anemia OR autoimmune hemolytic anemia. Of all the abbreviations collected in the master list, it is the author's opinion that the list of fatal abbreviations is the most important to map. Once a programmer has a list of these abbreviations and their alternate expansions, it is exceedingly easy to write a program that will parse the abbreviations from medical text and append a listing of all the possible abbreviations that might be correctly or mistakenly applied.
Table 3. Fatal Abbreviations: Victims of Abbreviation Drift (http://www.julesberman.info/abbtwo.htm)
In summary, abbreviations can be classified according to the different algorithmic protocols needed to assign an expansion. This study lays the logical foundation for future work that collects the annotated abbreviations into object classes whose methods are the software implementations of the algorithmic approaches described herein. Any future efforts will need to take special account of the so-called fatal abbreviations (Table 3 ). When expanded incorrectly, these expansions may lead to medical errors. References 1. Berman JJ. Survey of medical abbreviations in pathology text. Arch Pathol Lab Med 2002;126:781-802. (abstract section). 2. Nadkarni P, Chen R, Brandt C. UMLS concept indexing for production databases. JAMIA 2001;8:80-91. 3. Liu H, Lussier YA, Friedman C. A Study of abbreviations in the UMLS. Proc AMIA Symp. 2001;393-397. 4. Wong RL, Reno JD, Hain TC, Platt RC, Gaynon PS, Joseph DM. Profile of a dictionary compiled from scanning over a million words of surgical pathology narrative text. Comp Biomed Res 1980;13:382�388. 5. Kretschmar CS. Ewing's sarcoma and the "peanut" tumors. New Engl J Med 1994;331:325�327.
Last modified: April 7, 2014
How do you abbreviate assignment? There is one common way to abbreviate assignment.
The plural abbreviation of assignment is asgmts.
When to Use This Abbreviation
This abbreviation is used in classrooms, note taking, business, and any time space is of concern. You might abbreviate the word assignment to asgmt. on a homework list or see such abbreviations in note taking , headlines, or newspaper columns.
Outside of note taking or headlines, the word is not abbreviated in general prose.
What Does Assignment Mean?
Definition of Assignment: Assignment is defined as a task or piece of work assigned to someone as part of a job or course of study; the attribution of someone or something as belonging.
- Eric had only two more pages of assigned reading but was too tired to follow the words in front of him and fell sound asleep in the arm chair.
- His assignment was to follow the waitress in order to train as a waiter.
The word assignment functions as a noun in the sentence.
Outside Examples of Assignment
- He spent time on “modified assignment” but was reinstated after paying the alleged bribe. –New York Post
- Real Estate heir Robert Durst has been assigned to an Indiana prison which has a medical unit, rather than the California prison requested because he faces a murder trial in Los Angeles, attorney Dick DeGuerin said Sunday. –New York Daily News
Summary: Assignment Abbreviation
There is one common abbreviation of assignment: asgmt. If you want to pluralize the abbreviation, simply add on an “s.”