Fans of medical-themed television shows, as well as fans of police procedurals, probably can’t go through watching a single episode of their favorite show without hearing the word follow-up. Yes, we also read it in the newspapers and online, and we hear it in our daily lives as well, but it seems that doctors and detectives do a heck of a lot of following up. Doctors schedule follow-up appointments to see how you’re doing after a treatment, and police officers follow up on leads. Journalists are known to report follow-up stories when they gather new information about an event they’ve already covered. And if you’ve noticed the difference in hyphen use between follow-up and follow up, it doesn’t have anything to do with being a doctor, a police officer, or a journalist:
Follow-up is a noun or an adjective;
Follow up is a verb.
Follow-up and How to Use It
Follow-up, when written with a hyphen, can be either a noun or an adjective. As a noun, it means something that is done in relation to previous activity:
It was an act of ravenous readership that summed up the public’s astonishing appetite today for The Lost Symbol, Dan Brown’s long-awaited follow-up to his bestselling The Da Vinci Code, which has been launched worldwide.
A two month follow-up revealed true cancer cells, leaving surgery as the only choice.
When we want to say that something is following up on an action or is related to a follow-up, we can use follow-up as an adjective:
Spark therapeutics announces publication of positive follow-up data from phase 1 trial of voretigene neparvovec in the lancet Source text for Eikon.
The Honolulu City Auditor’s office plans to conduct a follow-up audit of the Honolulu Authority for Rapid Transportation, the city agency overseeing the rail transit project, PBN has learned.
—Pacific Business News
Follow up and How to Use It
Follow up is a phrasal verb that can have one of several meanings:
To follow something with a complemental action, event, or object:
The major reason why pupils fail examinations is lack of personal effort and lack of confidence in themselves. They first have to develop that confidence which must then be followed up with personal effort.
To keep in touch with someone:
While all Madison police officers are trained in mental health response and de-escalation, about 20 officers act as volunteer liaisons who follow up with individuals in their service areas who have been contacted by police.
—Wisconsin State Journal
To pursue with intention of taking an action:
Investigations into the murders of eight men of Turkish descent, one man of Greek descent and a German police officer repeatedly failed to identify and follow up leads pointing to the racist motivation behind the attacks, while relatives of the victims reported feeling victimized by the police.
—Amnesty International USA
To take appropriate action on something:
The scandal began on 24 February when journalists from state television followed up on complaints from locals, and visited a farm in Sololuk District, not far from Bishkek.
from Grammarly Blog https://www.grammarly.com/blog/how-to-use-follow-up/