अनुवर्तन

Follow up means monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

It is a a subsequent examination of a patient for the purpose of monitoring earlier treatment.

अनु means later or after and परीक्षण means tests.
I think that the above equivalents are competent enough to convey the implied meaning here. It seems that some more tests are required to be undertaken afterwards once the patient has been discharged from the hospital in order to ensure that he is recovering from the disease. It is understood that the physicians would be conducting some additional tests during these follow-up visits to ascertain whether the patient is healing or not.

In medical tems follow up is nothing but to consult your doctor again and again