Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for new chest pain, sudden shortness of breath, fainting, coughing up blood, or stroke symptoms.
And for anyone, someone who:
Seek urgent assessment for new one-sided limb swelling or pain.
Follow-up usually reviews symptoms, medicine use, bleeding, test results, and the likely cause of the clot.
The clinician may also discuss when to return to work, travel, exercise, or other activities.
Routine follow-up is also a time to review whether treatment should continue and whether age-appropriate health screening is up to date.
Extensive cancer or genetic testing is not automatically needed for every clot.
These are not symptoms to save for a routine appointment.
The article also says
Tell every clinician and dentist about anticoagulant treatment before a procedure or new prescription.
Check before using over-the-counter pain relievers, supplements, or herbal products because some can increase bleeding or change how an anticoagulant works.
Do not skip, double, or change doses unless the prescribing team provides instructions.
Every sign above is quoted from the sofidex article on Blood clots. If you are not sure, err upward — it is always reasonable to be checked.