Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Emergency symptoms such as chest pain, severe shortness of breath, fainting, confusion, or uncontrolled bleeding require immediate care rather than waiting for a scheduled appointment.
Follow-up blood testing is used to see whether hemoglobin and reticulocyte production are improving.
The timing depends on the cause, treatment, severity, and whether other blood cell counts are abnormal.
Keep routine follow-up even if fatigue improves.
The blood count may recover before iron or vitamin stores are fully restored, and ongoing blood loss or poor absorption may cause anemia to return.
Arrange an earlier review if symptoms worsen, new bleeding appears, infections become frequent, or bruising develops.
The article also says
A rise in reticulocytes can be an early sign that the marrow is responding, while hemoglobin usually changes more gradually.
Clinicians may also repeat iron, vitamin, kidney, or inflammation tests.
People receiving erythropoiesis-stimulating medicines, transfusions, immunosuppressive therapy, or cancer treatment need condition-specific monitoring.
Every sign above is quoted from the sofidex article on Aregenerative anemia. If you are not sure, err upward — it is always reasonable to be checked.