Why “Post” is Not a Synonym for “After”

Usage is an important part of scientific and medical writing. Authors need to use the best words to ensure that their content is accurate and precise. In this way, their writing reflects their knowledge and professionalism.

Incorrect word usage can reflect poorly on authors. While editing for authors, I have noticed several words that are often used incorrectly, such as utilize or employ. But lately, I’ve noticed more authors attempt to use the word post as a synonym for after.

Example 1

Incorrect: The cells were lysed 3 days post treatment.

Example 2

Incorrect: The patient was discharged 1 week post surgery.

By its definition, post is not a synonym for after. As a noun, post refers to a sturdy piece of wood or metal (eg, fence post), a piece of content published online (eg, blog post), or perhaps a place of duty (eg, military post). As a verb, post means to display or publish something (eg, post a notice), or to send someone to a place of duty (eg, post a guard).

The incorrect usage of the word post as a synonym for after is likely a byproduct of the prefix post-. As a modifier (not a separate word), post- means after, later, or subsequent to. In this prefix form, post- can create synonymous meaning with after.

Example 3

Incorrect: The mice were treated 3 days post transplant.

Correct: The mice were treated 3 days post-transplant.

Also correct: The mice were treated 3 days after transplant.

Fixing the incorrect usage is a simple task. In some cases, you might be able to simply add a hyphen or delete a space. Be sure to check a dictionary to know which form is correct.

Example 4

Incorrect: The patient was discharged 1 week post surgery.

Correct: The patient was discharged 1 week post-surgery.

Example 5

Incorrect: The cells were lysed 3 days post treatment.

Correct: The cells were lysed 3 days posttreatment.

In other cases, you might find that adding a hyphen creates awkward wording. In these cases, use the word after instead of the prefix form of post-.

Example 6

Incorrect: The cells were imaged 2 days post procedure.

Avoid: The cells were imaged 2 days post-procedure.

Better: The cells were imaged 2 days after the procedure.

Example 7

Incorrect: The patient was given the drug 5 days post liver resection

Avoid: The patient was given the drug 5 days post-liver resection.

Better: The patient was given the drug 5 days after liver resection.