Abbreviations can be dangerous. The number of acronyms used in clinical conversation is steadily increasing. Some acronyms have two meanings. What is a frequently used term in one hospital may not be used in another. With shortening of a term, some information is always lost, and use can cause confusion and even affect the safety of patients. There are acronyms which use the same letters, but have different meanings. For example, we noted in Module two that LOC usually refers to level of consciousness. But someone might use it intending to mean loss of consciousness. This abbreviation is used verbally and could make a difference in how you approach or take care of a patient. If you hear this, or any abbreviation that you are not clear about, don't hesitate to ask for clarification. Simply say, please clarify what you mean by LOC. You have learned that BS, used in the context of medical or nursing assessment, is usually bowel sounds. However, in some settings, BS might mean breath sounds. Since this is a written abbreviation, generally you will be able to look at the context in which it is used, and determine if the lungs or the bowels are being described. A similar situation is evident for a frequently misused acronym, DOA, which can mean day of admission or dead on arrival. You are likely to hear DOA in conversation, so you need to consider the context. If someone is saying she is really distressed her father arrived DOA in the ER this morning. You can infer the meaning. On the other hand if someone uses DOA while talking about your very much alive patient then the conversation is about his date of a vision. Abbreviations can cause medication errors. For example, the abbreviation HS generally referring to hour of sleep or bedtime might be confused with HS used to indicate half strength. The confusing HS may be part of a physician's order. Don't guess. Seek clarification, or consider how DC might mean discontinue or discharge. Nurses who are interpreting physicians' orders must always seek clarification. The use of abbreviations as part of doctors' orders is so problematic, that one national accrediting organization has issued a list of abbreviations that doctors are encouraged not to use. Module five focuses on abbreviated, common, laboratory tests. One way to help remember the source of the acronym is to associate each with the body organ function that it is measuring. A more complete list of common laboratory tests and their normal values is included as a study guide at the end of module five.