1. Use a colon after a heading, followed by a space. (Some prefer two spaces after a colon or period.)
CHIEF COMPLAINT: Left-sided paralysis.
2. When a complete sentence ends with the words as follows or the following, use a colon and then continue with the list or series that follows.
His symptoms include all of the following: dyspnea on exertion, fatigue, and productive cough.
3. Do not use a colon between a verb and a list that follows.
His symptoms include exertion, fatigue, and productive cough.
4. Use a colon to express a ratio (a mathematical expression showing the relationship of one part to another).
Xylocaine 1:100,000 was instilled. (Indicates that there is one part Xylocaine to 100,000 parts solution.)
A/G ratio was 2.1.
Albumin-globulin ratio was 2.1.
Note: Only the ratio value uses the colon; the actual laboratory test uses a slash mark or hyphen.
5. Use a colon to express hours and minutes, but do not use a colon with military time.
The patient was admitted to the emergency department at 2:20 a.m.
The patient was admitted at 1420 hours.