Problem: The English language uses the Latin alphabet with 26 letters and a numeric system with 10 numerals. These alphanumeric symbols (letters and numerals) work well most of the time when used to communicate information. However, problems may arise during written or electronic communication because of similarities in appearance of the alphanumeric symbols we use. For example, depending on the font, the lowercase letter l can look exactly like the numeral 1. The uppercase letter O looks like the numeral 0. Since many alphanumeric symbols share similar, or identical, physical characteristics, differentiation often poses a challenge. Table 1lists examples of commonly confused alphanumeric symbols.
Handwritten Communication
Mistaken letters and numerals play a large part in errors when reading handwritten drug names, doses, and directions. Cursive writing is most susceptible to illegibility and carries the greatest vulnerability to error, as the various symbols often lack distinctiveness.1-3 A few examples of misinterpreted alphanumeric symbols that happened when reading handwritten medication orders follow.
Lowercase letter l mistaken as numeral 1. A nurse misread an order for 2 mg of AMARYL (glimepiride) as 12 mg (Figure 1).3
The lowercase l at the end of the brand name, along with insufficient space between the last letter of the drug name and the dose, led the nurse to misread the dose as 12 mg. The pharmacist processed the order correctly as 2 mg, and the error was detected when the nurse called to question why only 2 mg was dispensed.
In another case, a nurse transcribed an order for lisinopril 2.5 mg daily by copying the prescriber’s orders that were previously on hold. However, she misread the dose as 12.5 mg daily (Figure 2),seeing the final “l” in lisinopril as the number one (1). The patient received several incorrect doses and developed hypotension, which required monitoring. Similar dosing errors have occurredwith other drugs with names that end in the letter l (Figure 3 provides another example).4
Uppercase letter L mistaken as uppercase letter I. While reviewing an order for a new patient, a pharmacist read “IODINE” in the space for allergies. Another pharmacist thought the allergy was LODINE (etodolac). The pharmacist contacted the patient’s physician who identified Lodine as the allergy.2 The patient was not harmed, but failure to document the correct allergy could have risked serious harm.
Uppercase and lowercase letter U mistaken as numerals 0 or 4. Another common mix-up between alphanumeric letters and numerals involves an uppercase U or lowercase u that has been mistaken as the numeral 0 or 4 if the downward tail on the letter U/u is too long. The handwritten order in Figure 4was misread as NOVOLOG (insulin aspart) 54 units instead of the intended 5 units. 
The word “units” had been written out, but the letter u looked like the numeral 4, and the remaining part of the word, “nits,” was read as units. The mistake was made by three practitioners who either dispensed or administered the medication. The patient required treatment for severe hypoglycemia. This error occurred despite the prescriber’s avoidance of the error-prone abbreviation U for units, which has also been misinterpreted as the numeral 4 or 0.
Uppercase letter Z mistaken as numeral 2. A handwritten order for hydrochlorothiazide 50 mg daily was mistaken as hydrocortisone 250 mg. An error-prone abbreviation for hydrochlorothiazide was used—HCTZ—and the dose was written very close to the abbreviation—HCTZ50. In this case, the handwritten letter Z was misread as the numeral 2.
Numeral 0 (written as Ø) mistaken as numeral 4, 9, or 6. A physician documented a handwritten null sign next to a dose prompt for a basal rate on a patient-controlled analgesia order form. Two nurses misread the null sign as the number 4. The patient received a basal infusion of morphine 4 mg/hour and became unresponsive. The patient was found in cardiac arrest; resuscitation efforts ensued but the patient suffered anoxic brain injury. During investigation of the event, several other orders with a null sign revealed that the symbol could be mistaken as a 4 or 9, especially if the tail of the slash mark through the circle is long, or a 6, especially if the circle is not closed above the slash mark through the circle.
Uppercase letter S mistaken as uppercase letter L. A handwritten order for SORIATANE (acitretin) 25 mg was mistaken as LOXITANE (loxapine) 25 mg. The cursive uppercase letters S and L, and the cursive lowercase letters “ri” and “xi,” looked very similar, leading to a potentially harmful error.
Electronic Communication
Electronic medical records, computer-generated or electronic medication administration records (eMARs), and computerized prescriber order entry can help overcome many problems with hand-written communication. Use of such technology has been swiftly growing in hospitals, thanks in large part to meaningful use incentives. However, even typed, computer-generated, or electronic prescriber orders and transcriptions may not prevent confusion among certain alphanumeric symbols. For example, a clearly typed prescription for 25 mcg of LEVOXYL (levothyroxine) could still be misread as 125 mcg if it appears without proper spacing as Levoxyl25 mcg, especially since both strengths are available for this medication.
To cite another example, those familiar with computer-generated passwords know how easy it is to misidentify a lowercase letter l in a password (or email address) as the numeral 1, or the letter O as a numeral 0.Information that contains both numerals and letters—including a medication order—is particularly prone to errors.
Risk Factors Leading to Confusion
The probability of confusing one alphanumeric symbol with another is largely dependent on the number of distinguishing factors between the look-alike pair. The fewer the distinguishing factors, the greater the risk of confusion. For example, the letter O and numeral 0 are at high risk for confusion because there are no discernable factors between them.
It is also more likely for an alphanumeric symbol with more distinguishing factors to be misread as its look-alike counterpart with fewer distinguishing elements.5 Take the number pair of 8 and 3. If the features of these numerals are segmented into rectilinear configurations (like the numbers on digital clocks), the numeral 8 would touch upon all 7 segments, and the numeral 3 would touch upon 5 of the 7 segments (Figure 5). 
Thus, the numeral 8 would have a greater probability of being misread as the numeral 3, rather than vice versa. The alphanumeric symbol not recognized correctly is more often perceived as one with a simpler configuration.
Context is also a risk factor. While context can sometimes enhance symbol recognition, it can also detract from recognition. For example, if you saw a Z, I, or O amid an array of numerals, you could easily mistake the symbols as the numerals 2, 1, or 0. Also, word recognition software often has difficulty distinguishing L and I, Z and 2, and other look-alike symbols.
Thus, it is not surprising that research conducted by Bell Laboratories found that some alphanumeric symbols are more vulnerable than others to misidentification.1 The symbols l and 1, O and 0, Z and 2, and 1 and 7 accounted for more than half of the errors caused by symbol misidentification in the study.
Safe Practice Recommendations
The characteristics of alphanumeric symbols that form each word or number determine the accuracy and speed at which material may be read or identified. Clarity around the following three characteristics allows readers to focus on the message instead of the mechanics of reading:6
- Visibility: The quality of an alphanumeric symbol that makes it separately discernable from its surroundings.
- Legibility: The attribute of an alphanumeric symbol that makes it possible for each character to be recognized.
- Readability: The quality that makes possible the recognition of the information content of the material.
There are various ways to promote these characteristics in written communications.
Use lowercase or mixed-case letters. Avoid using all uppercase letters. The brain recognizes written words by the shape of the word, or its coastline.7 Coastline refers to the shape of a word formed by the boundaries of its letters. When using all uppercase letters, a word’s shape or coastline is not offered as a visual clue to aid in word recognition.7 While there are several handwritten lowercase letters that are difficult to distinguish (Table 1, above), lowercase letters in general offer more differentiation than uppercase letters. Mixed-case letters (as with capitalizing the first letter of brand names, or using tall man lettering) also provide better distinction among letters. Practically all the text we read is in lowercase or mixed-case letters, so readers are used to that format.7 Words in all uppercase letters may have a small role in use for emphasis.
Print. Encourage prescribers to clearly print handwritten orders, and encourage nurses to use printing when transcribing orders. Practitioners may save time by using cursive writing, but the time saved needs to be weighed against the risk of errors and the tremendous waste of staff time when poorly handwritten orders must be interpreted.
Provide lightly lined order forms. Lines on forms for handwritten orders should be lightly shaded, making them visible to prescribers, yet still light enough to prevent interference with symbols—particularly T, 7, and I, or E, F, and L—when reading handwritten and faxed orders.
Use symbolic differentiation carefully. Symbolic differentiation may be another way to distinctively convey a symbol’s meaning.1 For example, the numeral 7 can be written with a bar through it to prevent confusion with the numeral 1. The letter Z with a bar through it also can prevent confusion with the numeral 2. However, avoid using a symbolic null sign (Ø) in place of the numeral 0, as it’s prone to confusion.
Be selective about font and typeface. Sans Serif fonts are easier to read on computers, although a Roman-style Serif font is easier to read on printed text.7 The Roman-style Serif font (e.g., font) is widely used, very legible, and provides high discrimination between alphanumeric characters. But Serif fonts more elaborate than this style should not be used.6 The preferred font size is about 20-25 minutes of arc, which is equivalent to a 10-14 point font size.6 A study comparing typefaces and font sizes found that, at the 10 point size, Verdana (e.g., font) or Tahoma (e.g., font) was preferred; at the 12 point size, Arial (e.g., font) or Courier (e.g., font) was preferred; and at the 14 point size, Comic Sans (e.g., font) was preferred.7 Times New Roman (e.g., font) and Arial (e.g., font) were read the fastest. Out of all the fonts, Arial (e.g., font) and Courier (e.g., font) were found to be the most legible. (Accurate examples for font size and typeface are in the PDF version of the newsletter.)
Avoid italics and underlining. Italics or underlining should be avoided, as they make it more difficult for the reader to recognize the word shape. However, italics for words or clauses may be used according to publishing guidelines (e.g., Latin terms, journal titles, bacteria nomenclature).
Ensure proper spacing. Allow proper space between the individual letters of a drug name and between the drug name and the dose on all handwritten prescriptions, printed prescriptions and preprinted order sets, and electronic formats such as computer screens, computer-generated medication labels and MARs, printed forms/order sets, and shelf labels. Also provide enough space between each line of text so that tails, loops, and bars of letters do not interfere with the letters in words in lines above and below the text.
Ensure drug and dose make sense. When reading an order, determine if the dose is within a recommended range and available in the strength prescribed. If not, follow-up with the prescriber may be necessary to clarify the order. Keep in mind that the context in which the order is read may not be helpful in all cases to properly identify alphanumeric symbols; however, in the case of medication orders, context may help raise a red flag if the dose seems too high or too low.
References
- Nierenberg GI. Do it right the first time. New York: John Wiley and Sons; 1996:154-62.
- ISMP. Misidentification of alphanumeric characters. ISMP Medication Safety Alert! Community/Ambulatory Care Edition. 2003;2(1):3.
- ISMP. Misidentification of alphanumeric symbols in both handwritten and computer-generated information. ISMP Medication Safety Alert! 2009;14(13):1-2.
- Pennsylvania Patient Safety Authority. What the “l” is the dose? PA PSRS Patient Saf Advis. 2006; 3(3):19-20.
- Keren G, Baggen S. Recognition models of alphanumeric characters. Perception & Psychophysics. 1981;29(3):234-46.
- Kelly MJ. Preliminary Human Factors Guidelines for Traffic Management Centers. Electronic Systems Laboratory, for US Federal Highway Administration;1999.
- Oberoi A. How typography affects readers. Adpushup.com Accessed June 1, 2014.
FAQs
What is alphanumeric keys example? ›
Alphanumeric characters are the numbers 0-9 and letters A-Z (both uppercase and lowercase). An alphanumeric example are the characters a, H, 0, 5 and k.
What letters can be confused with numbers? ›For example, the letters Z, I, and O, amid an array of numerals, can easily be mistaken for the numbers 2, 1, and 0. It may also be difficult for word-recognition software to distinguish L from I, Z from 2, and other look-alike symbols from each other.
What is alphanumeric format? ›Alphanumeric, also referred to as alphameric, is a term that encompasses all of the letters and numerals in a given language set. In layouts designed for English language users, alphanumeric characters are those comprised of the combined set of the 26 alphabetic characters, A to Z, and the 10 Arabic numerals, 0 to 9.
Are alphanumeric characters used to present information? ›Alphanumeric characters refers to the 26-letter Latin alphabet, the numerical digits from 0-9, and sometimes special characters including @, #, and *. These characters are often used in passwords to information systems or in filenames.
How do you know if something is alphanumeric? ›The isalnum() method returns True if all the characters are alphanumeric, meaning alphabet letter (a-z) and numbers (0-9). Example of characters that are not alphanumeric: (space)! #%&? etc.
What are alphanumeric keys answer? ›Typing (alphanumeric) keys.
These keys include the same letter, number, punctuation, and symbol keys found on a traditional typewriter.
For instance, number “4” can be used instead of letter “A”, number “8” can be used as letter “B” or lowercase “g”, 7 can be used as letter “T”, 5 can be used as letter “S” and 1 can be used as letter “I” according to their shape resembles to the letters.
What symbols can replace letters? ›...
Password Tips
- $, S or 5 for s.
- 1, I or ! for i.
- @ or A for a.
- 7 or T for t.
- 3 or E for e.
- 9, G or 6 for g.
- 0 or O for o.
- 8 or B for b.
Dyslexia can affect writing and spelling, too. It can also impact math. A learning difference that causes trouble with making sense of numbers and math concepts. Struggling with reading can make kids feel inferior to their peers and can impact self-esteem.
Which is the correct order in alphanumeric outlining? ›Alphanumeric Outlines
The formatting follows these characters, in this order: Level 1: Roman Numerals (I, II, III, IV, V, etc.) Level 2: Capitalized Letters (A, B, C, D, E, etc.) Level 3: Arabic Numerals (1, 2, 3, 4, 5, etc.)
What are the types of alphanumeric? ›
| Character | Description | Characters Allowed |
|---|---|---|
| X | Alphanumeric | All characters |
| U | Uppercase alphanumeric | All characters — automatically converted to uppercase |
| L | Lowercase alphanumeric | All characters — automatically converted to lowercase |
| 9 | Number | Digits, local decimal point, sign, space |
The first letter of the word, group of words, or sentence that follows each symbol is capitalized. Main ideas are listed as Roman numerals on the left margin and are followed by periods. Examples: I. II.
Which is the most commonly used code for representing alphanumeric information? ›The ASCII code is an alphanumeric code used for data communication in digital computers. The ASCII is a 7-bit code capable of representing 27 or 128 number of different characters.
Which of the following is the most widely used alphanumeric? ›The most widely used 7-bit alphanumeric code is ASCII code.
Is alphanumeric the same as text? ›Alphanumeric is frequently used to describe the type of text that is available for use or entry in a field, such as an alphanumeric password field. A character set with alphabetic (A-Z) and numeric characters is known as an alphanumeric character set (0-9).
What is not an alphanumeric character? ›Non-alphanumeric characters are characters that are not numbers (0-9) or alphabetic characters.
What comes first in alphanumeric? ›Books are arranged on the shelves in that alphanumeric order, which means that the letter order follows alphabetical order (A-Z) and smaller numbers come before larger numbers.
How do you write names in alphanumeric characters? ›There is no one definitive way to write your name in alphanumeric characters. However, some tips on how to do so are to use all capital letters, use underscores to separate words, and to use numbers or special characters in place of letters that are difficult to pronounce or read.
What is an alphanumeric keyboard assessment? ›The Alphanumeric Data Entry (Visual) skills test is a fast, easy way to confirm whether a candidate has the ability to enter data quickly and accurately while reading from the screen. The test asks questions pulled from a bank of questions for testing security purposes.
What are alphanumeric questions? ›Alphanumeric series questions are a combination of numbers, alphabets and symbol-based series which candidates need to answer the questions based on the series. One of the most frequently asked topics in the various Government exams, the alphanumeric series general cover 2-3 questions in the reasoning ability section.
How do you use alphanumeric keys? ›
Alphanumeric keys: These are used for typing letters, numbers and notations into the computer. The various keys in the alphanumeric keys are: Letter keys: The letter keys (A-Z) work like the typewriter. When the letter keys are pressed alone, the lower case type appear on the screen.
What number looks like V? ›The use of Roman Numerals in Plate Design
V, is the Roman symbol for 5, X means 10, L means 50, and M is 1,000.
1337 is a language for internet users known for replacing letters with numbers or symbols. The term itself has gone on as a slang term for “extremely skilled (at gaming or computing)” or, more generally, “awesome.”
What number replaces G? ›The number '6' is the number most use as the letter 'G'. Simply because it looks like a 'G' in most countries font styles. We have two possible letters which '8' could replace. Either the letter 'O' or 'B'.
How do you replace words with symbols? ›Note: Select the arrow at the bottom of the Find and Replace dialog box to show all options. On the Special menu, select the special character that you want to find. Select in the Replace with box. On the Special menu, select the special character that you want to use as a replacement.
Why are symbols used instead of words? ›Symbol-based communication is often used by individuals who are unable to communicate using speech alone and who have not yet developed, or have difficulty developing literacy skills. Symbols offer a visual representation of a word or idea.
How do you write letters with symbols? ›...
Keyboard shortcuts to add language accent marks in Word and Outlook.
| To insert this | Press |
|---|---|
| â, ê, î, ô, û Â, Ê, Î, Ô, Û | CTRL+SHIFT+^ (CARET), the letter |
| ã, ñ, õ Ã, Ñ, Õ | CTRL+SHIFT+~ (TILDE), the letter |
Common mistakes when reading and spelling are mixing up b's and d's, or similar looking words such as 'was' and 'saw', 'how' and 'who'. Letters and numbers can be written back-to-front or upside down.
What are signs of dyspraxia? ›Problems with movement and co-ordination are the main symptoms of DCD. Children may have difficulty with: playground activities such as hopping, jumping, running, and catching or kicking a ball. They often avoid joining in because of their lack of co-ordination and may find physical education difficult.
What is Hyperlexic? ›Hyperlexia is advanced and unexpected reading skills and abilities in children way beyond their chronological age. It is a fairly recently named condition (1967) although earlier descriptions of precocious reading do exist.
What is one important rule of outlining? ›
All outlines should begin with a thesis statement of summarizing sentence. This thesis sentence presents the central idea of the paper. It must always be a complete, grammatical sentence, specific and brief, which expresses the point of view you are taking towards the subject.
What are the three rules of outlining? ›CENTRAL IDEA: The three major principles for outlining a speech are having the right parts, using proper outlining form, and properly documenting sources.
How do you outline an answer? ›outline answer requires you present an organised description of a research topic or argument. It is imperative that you provide the main points only (and any important supplementary information) as opposed to focusing on the minor details. Remember to present your answer in a systematic and coherent way.
What does alphanumeric only means? ›: consisting of both letters and numbers and often other symbols (such as punctuation marks and mathematical symbols)
What is the opposite of alphanumeric? ›Non-Alphanumeric characters are the other characters on your keyboard that aren't letters or numbers, e.g. commas, brackets, space, asterisk and so on. Any character that is not a number or letter (in upper or lower case) is non-alphanumeric.
What is the difference between numeric and alphanumeric? ›Int'l Uppercase Alphanumeric – field accepts only uppercase alphabetic characters and numbers from an international keyboard; all inputted text will be converted to uppercase. Multi-line Text - field accepts multiple lines of text. Numeric – field accepts only numbers and specific numeric data entry characters.
Which of the following is the correct example of alphanumeric data? ›When something is made of both letters and numbers, it is alphanumeric. So, that means when a password is "p@ssw0rd" or a license plate is "123-ABC", they contain alphanumeric characters.
How do you use alphanumeric in a sentence? ›All routes are alphanumeric, with the first letter denoting the standard or function of the road. Such identification may be solely numeric or may contain a combination of letters and numbers (alphanumeric).
What is a sequence of alphanumeric characters? ›Alphanumeric sequence is a sequence which consists of both alphabets and numbers. In this sequence, we can also add some symbols along with alphabets and numbers. In the above sequence, we can see that there are numbers, alphabets, and symbols. These types of sequences are called alphanumeric sequence.
What is the importance of alphanumeric codes? ›The codes write alphanumeric data, including letters of the alphabet, numbers, mathematical symbols and punctuation marks, in a form that is understandable and process able by a computer. Using these codes, we can interface input-output devices such as keyboards, monitors, printers etc.
How do you read alphanumeric codes? ›
The alphanumeric character display is shown by the three or four digits. The first numeral shows 10 digits, the second numeral shows 1 digit, and the third numeral shows the multiplier in the three digit display.
How do you decode alphanumeric codes? ›The decryption of the base 36 consists of the conversion of coded numbers from the base 10 to the base 36 . Example: Decode the message 527198 . 527198=11×363+10×362+28×361+14×360 527198 = 11 × 36 3 + 10 × 36 2 + 28 × 36 1 + 14 × 36 0 so [11,10,28,14] in base 36 and 11=B , 10=A , 28=S , 14=E .
What are examples of alphanumeric codes? ›An alphanumeric example are the characters a, H, 0, 5 and k. These characters are contrasted to non-alphanumeric ones, which are anything other than letters and numbers. Examples of non-alphanumeric numbers include &, $, @, -, %, *, and empty space.
How many alphanumeric codes are there? ›Mostly such codes also represent other characters such as symbol and various instructions necessary for conveying information. An alphanumeric code should at least represent 10 digits and 26 letters of alphabet i.e. total 36 items.
What language uses alphanumeric? ›Assembly Language: The set of instruction codes written in alphanumeric symbols instead of 0's and 1' s. Meaningful and easily remember able symbols are selected for this purpose. For example, ADD for addition, SUB for subtraction etc. Such symbols are also known as mnemonic codes.
What is alphanumeric with symbols? ›Alphanumeric Defined
Alphanumeric, also known as alphameric, simply refers to the type of Latin and Arabic characters representing the numbers 0 - 9, the letters A - Z (both uppercase and lowercase), and some common symbols such as @ # * and &.
Alphanumeric Outlines
The formatting follows these characters, in this order: Roman Numerals. Capitalized Letters. Arabic Numerals. Lowercase Letters.
These are keys of all the alphabets (a – z) and numbers (0 – 9). The alphanumeric keys also include symbols at the upper part of the number row such as exclamation mark (!), at (@), ampersand (&) etc.
What is a good alphanumeric password? ›Both numbers and letters must be set. However, using a “Strong Alphanumeric” password that includes lowercase letters, capital letters, digits, and special characters (@, #, &, etc.) is always recommended. These four character kinds are collectively known as complicated characters.
What is the 8 digit alphanumeric code? ›It is 8-bit code in which the numerals (0-9) are represented by the 8421 BCD code preceded by 1111. Since it is a 8-bit code, it can almost represent 23 (= 256) different characters which include both lowercase and uppercase letters in addition to various other symbols and commands.
How many alphanumeric keys are there? ›
A standard alphanumeric keyboard has 101-104 keys.
Does alphanumeric mean special characters? ›An alphanumeric password contains numbers, letters, and special characters (like an ampersand or hashtag). In theory, alphanumeric passwords are harder to crack than those containing just letters.
How do you write your name in alphanumeric? ›...
Here are some general guidelines:
- Use only alphanumeric characters: You can use letters and numbers, but not special characters or symbols.
- Capitalize the first letter of each word: This will help make your name easier to read.
Alphanumeric Outlines use numbers, letters, and periods to organize information. The first letter of the word, group of words, or sentence that follows each symbol is capitalized. Main ideas are listed as Roman numerals on the left margin and are followed by periods.
What is 10 digit alphanumeric number? ›PAN is a 10 digit unique alphanumeric number issued by the Income Tax Department under the Indian Income Tax Act 1961. The first three characters are normal letters starting from AAA to ZZZ. The Department of I.T allocates the digits randomly which is a combination of the letters like AZT or ZRT.
What are the most common alphanumeric codes? ›The most common alphanumeric codes used these days are ASCII code, EBCDIC code, and UNICODE.
How many combinations of 8 alphanumeric characters are there? ›You want to write a string of 8 characters. Each character can be a letter between A-Z (26 options), therefore, there are 26^8 combinations: 26*26*26*... 26 . That is 208827064576 combinations.
How many combinations of 4 alphanumeric characters are there? ›Answer and Explanation: The number of possible combinations that are possible with 4 letters is 14,950.
How many combinations of 2 alphanumeric characters are there? ›Answer and Explanation: There are 325 possible combinations with two letters. To determine this number of combinations, we use the fact that the alphabet has 26 letters.
How many combinations of 5 alphanumeric characters are there? ›Answer and Explanation: The number of combinations possible with 5 letters is 65,780.