37 yr old female very low iron in recent blood test.gp prescribed ferrous fumarate once a day.after 30 days she needs a ferritin test to check iron levels should she stop taking the tablets before blood test or carry on taking them want accurate test?

I would continue to take the med until you are told to stop it. It often takes up to 3 months or more to restore the normal iron reserves to someone who is anemic. The med itself will not alter the test while you take it.

Continue taking iron. You do not need to fast for blood iron level test either. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!